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ValueSet
default
Risk of harmful or undesirable, physiological response which is unique to an individual and associated with exposure to a substance.
AllergyIntolerance
Path
AllergyIntolerance
Id
AllergyIntolerance
Cardinality
0 - *
Definition
Risk of harmful or undesirable physiological response which is specific to an individual and associated with exposure to a substance.
Comment
Substances include, but are not limited to: a therapeutic substance administered correctly at an appropriate dosage for the individual; food; material derived from plants or animals; or venom from insect stings.
Constraint
dom-2 [error]
If the resource is contained in another resource, it SHALL NOT contain nested Resources
dom-3 [error]
If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource
dom-4 [error]
If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated
dom-5 [error]
If a resource is contained in another resource, it SHALL NOT have a security label
dom-6 [warning]
A resource should have narrative for robust management
Path
AllergyIntolerance.identifier
Id
AllergyIntolerance.identifier
Type
Cardinality
0 - *
Definition
Business identifiers assigned to this AllergyIntolerance by the performer or other systems which remain constant as the resource is updated and propagates from server to server.
Comment
This is a business identifier, not a resource identifier (see [discussion](resource.html#identifiers)). It is best practice for the identifier to only appear on a single resource instance, however business practices may occasionally dictate that multiple resource instances with the same identifier can exist - possibly even with different resource types. For example, multiple Patient and a Person resource instance might share the same social insurance number.
Requirements
Allows identification of the AllergyIntolerance as it is known by various participating systems and in a way that remains consistent across servers.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.use
Id
Identifier.use
Type
Cardinality
0 - 1
Definition
The purpose of this identifier.
Comment
Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.
Requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.
Binding
Strength
required
Description
Identifies the purpose for this identifier, if known .
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.type
Id
Identifier.type
Type
Cardinality
0 - 1
Definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.
Comment
This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.
Requirements
Allows users to make use of identifiers when the identifier system is not known.
Binding
Strength
extensible
Description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.type.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.type.CodeableConcept.coding.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
Comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should be an absolute reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.type.CodeableConcept.coding.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
Definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.type.CodeableConcept.coding.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
Definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.identifier.Identifier.type.CodeableConcept.coding.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.identifier.Identifier.type.CodeableConcept.coding.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, an absolute URL that describes a set values that are unique.
Comment
Identifier.system is always case sensitive.
Requirements
There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.value
Id
Identifier.value
Type
Cardinality
0 - 1
Definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.
Comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the [http://hl7.org/fhir/StructureDefinition/rendered-value](http://hl7.org/fhir/extensions/StructureDefinition-rendered-value.html)). Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ident-1
Path
AllergyIntolerance.identifier.Identifier.period
Id
Identifier.period
Type
Cardinality
0 - 1
Definition
Time period during which identifier is/was valid for use.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.period.Period.start
Id
Period.start
Type
Cardinality
0 - 1
Definition
The start of the period. The boundary is inclusive.
Comment
If the low element is missing, the meaning is that the low boundary is not known.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
per-1
Path
AllergyIntolerance.identifier.Identifier.period.Period.end
Id
Period.end
Type
Cardinality
0 - 1
Definition
The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.
Comment
The end value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
per-1
Path
AllergyIntolerance.identifier.Identifier.assigner
Id
Identifier.assigner
Type
Cardinality
0 - 1
Definition
Organization that issued/manages the identifier.
Comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.identifier.Identifier.use
Id
Identifier.use
Type
Cardinality
0 - 1
Definition
The purpose of this identifier.
Comment
Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.
Requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.
Binding
Strength
required
Description
Identifies the purpose for this identifier, if known .
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.identifier.Identifier.type
Id
Identifier.type
Type
Cardinality
0 - 1
Definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.
Comment
This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.
Requirements
Allows users to make use of identifiers when the identifier system is not known.
Binding
Strength
extensible
Description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, an absolute URL that describes a set values that are unique.
Comment
Identifier.system is always case sensitive.
Requirements
There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.identifier.Identifier.value
Id
Identifier.value
Type
Cardinality
0 - 1
Definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.
Comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the [http://hl7.org/fhir/StructureDefinition/rendered-value](http://hl7.org/fhir/extensions/StructureDefinition-rendered-value.html)). Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ident-1
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.identifier.Identifier.period
Id
Identifier.period
Type
Cardinality
0 - 1
Definition
Time period during which identifier is/was valid for use.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.identifier.Identifier.assigner
Id
Identifier.assigner
Type
Cardinality
0 - 1
Definition
Organization that issued/manages the identifier.
Comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.identifier.Identifier.assigner.Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.clinicalStatus
Id
AllergyIntolerance.clinicalStatus
Type
Cardinality
0 - 1
Definition
The clinical status of the allergy or intolerance.
Comment
AllergyIntolerance.clinicalStatus should be present if verificationStatus is not entered-in-error and the AllergyIntolerance.code isn't negated (No Known Allergy, No Drug Allergy, No Food Allergy, No Latex Allergy).
Refer to [discussion](extensibility.html#Special-Case) if clinicalStatus is missing data.
The data type is CodeableConcept because clinicalStatus has some clinical judgment involved, such that there might need to be more specificity than the required FHIR value set allows. For example, a SNOMED coding might allow for additional specificity.
Binding
Strength
required
Description
The clinical status of the allergy or intolerance.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.clinicalStatus.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.clinicalStatus.CodeableConcept.coding.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
Comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should be an absolute reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.clinicalStatus.CodeableConcept.coding.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
Definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.clinicalStatus.CodeableConcept.coding.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
Definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.clinicalStatus.CodeableConcept.coding.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.clinicalStatus.CodeableConcept.coding.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.verificationStatus
Id
AllergyIntolerance.verificationStatus
Type
Cardinality
0 - 1
Definition
Assertion about certainty associated with the propensity, or potential risk, of a reaction to the identified substance (including pharmaceutical product). The verification status pertains to the allergy or intolerance, itself, not to any specific AllergyIntolerance attribute.
Comment
The data type is CodeableConcept because verificationStatus has some clinical judgment involved, such that there might need to be more specificity than the required FHIR value set allows. For example, a SNOMED coding might allow for additional specificity.
Binding
Strength
required
Description
Assertion about certainty associated with a propensity, or potential risk, of a reaction to the identified substance.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.verificationStatus.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.verificationStatus.CodeableConcept.coding.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
Comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should be an absolute reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.verificationStatus.CodeableConcept.coding.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
Definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.verificationStatus.CodeableConcept.coding.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
Definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.verificationStatus.CodeableConcept.coding.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.verificationStatus.CodeableConcept.coding.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.type
Id
AllergyIntolerance.type
Type
Cardinality
0 - 1
Definition
Identification of the underlying physiological mechanism for the reaction risk.
Comment
Allergic (typically immune-mediated) reactions have been traditionally regarded as an indicator for potential escalation to significant future risk. Contemporary knowledge suggests that some reactions previously thought to be immune-mediated are, in fact, non-immune, but in some cases can still pose a life threatening risk. It is acknowledged that many clinicians might not be in a position to distinguish the mechanism of a particular reaction. Often the term "allergy" is used rather generically and may overlap with the use of "intolerance" - in practice the boundaries between these two concepts might not be well-defined or understood. This data element is included nevertheless, because many legacy systems have captured this attribute. Immunologic testing may provide supporting evidence for the basis of the reaction and the causative substance, but no tests are 100% sensitive or specific for sensitivity to a particular substance. If, as is commonly the case, it is unclear whether the reaction is due to an allergy or an intolerance, then the type element should be omitted from the resource.
Binding
Strength
preferred
Description
Identification of the underlying physiological mechanism for a Reaction Risk.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.type.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.type.CodeableConcept.coding.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
Comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should be an absolute reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.type.CodeableConcept.coding.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
Definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.type.CodeableConcept.coding.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
Definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.type.CodeableConcept.coding.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.type.CodeableConcept.coding.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.category
Id
AllergyIntolerance.category
Type
Cardinality
0 - *
Definition
Category of the identified substance.
Comment
This data element has been included because it is currently being captured in some clinical systems. This data can be derived from the substance where coding systems are used, and is effectively redundant in that situation. When searching on category, consider the implications of AllergyIntolerance resources without a category. For example, when searching on category = medication, medication allergies that don't have a category valued will not be returned. Refer to [search](search.html) for more information on how to search category with a :missing modifier to get allergies that don't have a category. Additionally, category should be used with caution because category can be subjective based on the sender.
Binding
Strength
required
Description
Category of an identified substance associated with allergies or intolerances.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.criticality
Id
AllergyIntolerance.criticality
Type
Cardinality
0 - 1
Definition
Estimate of the potential clinical harm, or seriousness, of the reaction to the identified substance.
Comment
The default criticality value for any propensity to an adverse reaction should be 'Low Risk', indicating at the very least a relative contraindication to deliberate or voluntary exposure to the substance. 'High Risk' is flagged if the clinician has identified a propensity for a more serious or potentially life-threatening reaction, such as anaphylaxis, and implies an absolute contraindication to deliberate or voluntary exposure to the substance. If this element is missing, the criticality is unknown (though it may be known elsewhere). Systems that capture a severity at the condition level are actually representing the concept of criticality whereas the severity documented at the reaction level is representing the true reaction severity. Existing systems that are capturing both condition criticality and reaction severity may use the term "severity" to represent both. Criticality is the worst it could be in the future (i.e. situation-agnostic) whereas severity is situation-dependent.
Binding
Strength
required
Description
Estimate of the potential clinical harm, or seriousness, of a reaction to an identified substance.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.code
Id
AllergyIntolerance.code
Type
Cardinality
0 - 1
Definition
Code for an allergy or intolerance statement (either a positive or a negated/excluded statement). This may be a code for a substance or pharmaceutical product that is considered to be responsible for the adverse reaction risk (e.g., "Latex"), an allergy or intolerance condition (e.g., "Latex allergy"), or a negated/excluded code for a specific substance or class (e.g., "No latex allergy") or a general or categorical negated statement (e.g., "No known allergy", "No known drug allergies"). Note: the substance for a specific reaction may be different from the substance identified as the cause of the risk, but it must be consistent with it. For instance, it may be a more specific substance (e.g. a brand medication) or a composite product that includes the identified substance. It must be clinically safe to only process the 'code' and ignore the 'reaction.substance'. If a receiving system is unable to confirm that AllergyIntolerance.reaction.substance falls within the semantic scope of AllergyIntolerance.code, then the receiving system should ignore AllergyIntolerance.reaction.substance.
Comment
It is strongly recommended that this element be populated using a terminology, where possible. For example, some terminologies used include RxNorm, SNOMED CT, DM+D, NDFRT, ICD-9, IDC-10, UNII, and ATC. Plain text should only be used if there is no appropriate terminology available. Additional details can be specified in the text.
When a substance or product code is specified for the 'code' element, the "default" semantic context is that this is a positive statement of an allergy or intolerance (depending on the value of the 'type' element, if present) condition to the specified substance/product. In the corresponding SNOMED CT allergy model, the specified substance/product is the target (destination) of the "Causative agent" relationship.
The 'substanceExposureRisk' extension is available as a structured and more flexible alternative to the 'code' element for making positive or negative allergy or intolerance statements. This extension provides the capability to make "no known allergy" (or "no risk of adverse reaction") statements regarding any coded substance/product (including cases when a pre-coordinated "no allergy to x" concept for that substance/product does not exist). If the 'substanceExposureRisk' extension is present, the AllergyIntolerance.code element SHALL be omitted.
Binding
Strength
example
Description
Type of the substance/product, allergy or intolerance condition, or negation/exclusion codes for reporting no known allergies.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.code.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.code.CodeableConcept.coding.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
Comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should be an absolute reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.code.CodeableConcept.coding.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
Definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.code.CodeableConcept.coding.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
Definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.code.CodeableConcept.coding.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.code.CodeableConcept.coding.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient
Id
AllergyIntolerance.patient
Type
Cardinality
1 - 1
Definition
The patient who has the allergy or intolerance.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.patient.Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.use
Id
Identifier.use
Type
Cardinality
0 - 1
Definition
The purpose of this identifier.
Comment
Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.
Requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.
Binding
Strength
required
Description
Identifies the purpose for this identifier, if known .
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.type
Id
Identifier.type
Type
Cardinality
0 - 1
Definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.
Comment
This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.
Requirements
Allows users to make use of identifiers when the identifier system is not known.
Binding
Strength
extensible
Description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.type.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, an absolute URL that describes a set values that are unique.
Comment
Identifier.system is always case sensitive.
Requirements
There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.value
Id
Identifier.value
Type
Cardinality
0 - 1
Definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.
Comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the [http://hl7.org/fhir/StructureDefinition/rendered-value](http://hl7.org/fhir/extensions/StructureDefinition-rendered-value.html)). Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ident-1
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.period
Id
Identifier.period
Type
Cardinality
0 - 1
Definition
Time period during which identifier is/was valid for use.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.period.Period.start
Id
Period.start
Type
Cardinality
0 - 1
Definition
The start of the period. The boundary is inclusive.
Comment
If the low element is missing, the meaning is that the low boundary is not known.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
per-1
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.period.Period.end
Id
Period.end
Type
Cardinality
0 - 1
Definition
The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.
Comment
The end value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
per-1
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.assigner
Id
Identifier.assigner
Type
Cardinality
0 - 1
Definition
Organization that issued/manages the identifier.
Comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.assigner.Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.assigner.Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.assigner.Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.patient.Reference.identifier.Identifier.assigner.Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.patient.Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.encounter
Id
AllergyIntolerance.encounter
Type
Cardinality
0 - 1
Definition
The encounter when the allergy or intolerance was asserted.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.encounter.Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.use
Id
Identifier.use
Type
Cardinality
0 - 1
Definition
The purpose of this identifier.
Comment
Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.
Requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.
Binding
Strength
required
Description
Identifies the purpose for this identifier, if known .
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.type
Id
Identifier.type
Type
Cardinality
0 - 1
Definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.
Comment
This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.
Requirements
Allows users to make use of identifiers when the identifier system is not known.
Binding
Strength
extensible
Description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.type.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, an absolute URL that describes a set values that are unique.
Comment
Identifier.system is always case sensitive.
Requirements
There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.value
Id
Identifier.value
Type
Cardinality
0 - 1
Definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.
Comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the [http://hl7.org/fhir/StructureDefinition/rendered-value](http://hl7.org/fhir/extensions/StructureDefinition-rendered-value.html)). Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ident-1
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.period
Id
Identifier.period
Type
Cardinality
0 - 1
Definition
Time period during which identifier is/was valid for use.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.period.Period.start
Id
Period.start
Type
Cardinality
0 - 1
Definition
The start of the period. The boundary is inclusive.
Comment
If the low element is missing, the meaning is that the low boundary is not known.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
per-1
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.period.Period.end
Id
Period.end
Type
Cardinality
0 - 1
Definition
The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.
Comment
The end value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
per-1
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.assigner
Id
Identifier.assigner
Type
Cardinality
0 - 1
Definition
Organization that issued/manages the identifier.
Comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.assigner.Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.assigner.Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.assigner.Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.encounter.Reference.identifier.Identifier.assigner.Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.encounter.Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.onset[x]
Id
AllergyIntolerance.onset[x]
Type
Cardinality
0 - 1
Definition
Estimated or actual date, date-time, or age when allergy or intolerance was identified.
Comment
Age is generally used when the patient reports an age at which the AllergyIntolerance was noted. Period is generally used to convey an imprecise onset that occurred within the time period. Range is generally used to convey an imprecise age range (e.g. 4 to 6 years old).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.recordedDate
Id
AllergyIntolerance.recordedDate
Type
Cardinality
0 - 1
Definition
The recordedDate represents when this particular AllergyIntolerance record was created in the system, which is often a system-generated date.
Comment
When onset date is unknown, recordedDate can be used to establish if the allergy or intolerance was present on or before a given date. If the recordedDate is known and provided by a sending system, it is preferred that the receiving system preserve that recordedDate value. If the recordedDate is not provided by the sending system, the receipt timestamp is sometimes used as the recordedDate.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
participant
Who or what participated in the activities related to the allergy or intolerance and how they were involved
Path
AllergyIntolerance.participant
Id
AllergyIntolerance.participant
Type
Cardinality
0 - *
Definition
Indicates who or what participated in the activities related to the allergy or intolerance and how they were involved.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.function
Id
AllergyIntolerance.participant.function
Type
Cardinality
0 - 1
Definition
Distinguishes the type of involvement of the actor in the activities related to the allergy or intolerance.
Comment
Binding
Strength
extensible
Description
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.function.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.function.CodeableConcept.coding.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
Comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should be an absolute reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.function.CodeableConcept.coding.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
Definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.function.CodeableConcept.coding.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
Definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.participant.function.CodeableConcept.coding.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.participant.function.CodeableConcept.coding.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.actor
Id
AllergyIntolerance.participant.actor
Type
Cardinality
1 - 1
Definition
Indicates who or what participated in the activities related to the allergy or intolerance.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.actor.Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.participant.actor.Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.actor.Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.participant.actor.Reference.identifier.Identifier.use
Id
Identifier.use
Type
Cardinality
0 - 1
Definition
The purpose of this identifier.
Comment
Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.
Requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.
Binding
Strength
required
Description
Identifies the purpose for this identifier, if known .
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.actor.Reference.identifier.Identifier.type
Id
Identifier.type
Type
Cardinality
0 - 1
Definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.
Comment
This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.
Requirements
Allows users to make use of identifiers when the identifier system is not known.
Binding
Strength
extensible
Description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.actor.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, an absolute URL that describes a set values that are unique.
Comment
Identifier.system is always case sensitive.
Requirements
There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.actor.Reference.identifier.Identifier.value
Id
Identifier.value
Type
Cardinality
0 - 1
Definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.
Comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the [http://hl7.org/fhir/StructureDefinition/rendered-value](http://hl7.org/fhir/extensions/StructureDefinition-rendered-value.html)). Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ident-1
Path
AllergyIntolerance.participant.actor.Reference.identifier.Identifier.period
Id
Identifier.period
Type
Cardinality
0 - 1
Definition
Time period during which identifier is/was valid for use.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.actor.Reference.identifier.Identifier.assigner
Id
Identifier.assigner
Type
Cardinality
0 - 1
Definition
Organization that issued/manages the identifier.
Comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.participant.actor.Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.lastOccurrence
Id
AllergyIntolerance.lastOccurrence
Type
Cardinality
0 - 1
Definition
Represents the date and/or time of the last known occurrence of a reaction event.
Comment
This date may be replicated by one of the Onset of Reaction dates. Where a textual representation of the date of last occurrence is required e.g. 'In Childhood, '10 years ago' the AllergyIntolerance.note element should be used.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note
Id
AllergyIntolerance.note
Type
Cardinality
0 - *
Definition
Additional narrative about the propensity for the Adverse Reaction, not captured in other fields.
Comment
For example: including reason for flagging a seriousness of 'High Risk'; and instructions related to future exposure or administration of the substance, such as administration within an Intensive Care Unit or under corticosteroid cover. The notes should be related to an allergy or intolerance as a condition in general and not related to any particular episode of it. For episode notes and descriptions, use AllergyIntolerance.event.description and AllergyIntolerance.event.notes.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note.Annotation.author[x]
Id
Annotation.author[x]
Type
Cardinality
0 - 1
Definition
The individual responsible for making the annotation.
Comment
Organization is used when there's no need for specific attribution as to who made the comment.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note.Annotation.author[x].Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.note.Annotation.author[x].Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note.Annotation.author[x].Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.note.Annotation.author[x].Reference.identifier.Identifier.use
Id
Identifier.use
Type
Cardinality
0 - 1
Definition
The purpose of this identifier.
Comment
Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.
Requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.
Binding
Strength
required
Description
Identifies the purpose for this identifier, if known .
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note.Annotation.author[x].Reference.identifier.Identifier.type
Id
Identifier.type
Type
Cardinality
0 - 1
Definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.
Comment
This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.
Requirements
Allows users to make use of identifiers when the identifier system is not known.
Binding
Strength
extensible
Description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note.Annotation.author[x].Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, an absolute URL that describes a set values that are unique.
Comment
Identifier.system is always case sensitive.
Requirements
There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note.Annotation.author[x].Reference.identifier.Identifier.value
Id
Identifier.value
Type
Cardinality
0 - 1
Definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.
Comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the [http://hl7.org/fhir/StructureDefinition/rendered-value](http://hl7.org/fhir/extensions/StructureDefinition-rendered-value.html)). Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ident-1
Path
AllergyIntolerance.note.Annotation.author[x].Reference.identifier.Identifier.period
Id
Identifier.period
Type
Cardinality
0 - 1
Definition
Time period during which identifier is/was valid for use.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note.Annotation.author[x].Reference.identifier.Identifier.assigner
Id
Identifier.assigner
Type
Cardinality
0 - 1
Definition
Organization that issued/manages the identifier.
Comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.note.Annotation.author[x].Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.note.Annotation.time
Id
Annotation.time
Type
Cardinality
0 - 1
Definition
Indicates when this particular annotation was made.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction
Id
AllergyIntolerance.reaction
Type
Cardinality
0 - *
Definition
Details about each adverse reaction event linked to exposure to the identified substance.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
substance
Specific substance or pharmaceutical product considered to be responsible for event
Path
AllergyIntolerance.reaction.substance
Id
AllergyIntolerance.reaction.substance
Type
Cardinality
0 - 1
Definition
Identification of the specific substance (or pharmaceutical product) considered to be responsible for the Adverse Reaction event. Note: the substance for a specific reaction may be different from the substance identified as the cause of the risk, but it must be consistent with it. For instance, it may be a more specific substance (e.g. a brand medication) or a composite product that includes the identified substance. It must be clinically safe to only process the 'code' and ignore the 'reaction.substance'. If a receiving system is unable to confirm that AllergyIntolerance.reaction.substance falls within the semantic scope of AllergyIntolerance.code, then the receiving system should ignore AllergyIntolerance.reaction.substance.
Comment
Coding of the specific substance (or pharmaceutical product) with a terminology capable of triggering decision support should be used wherever possible. The 'code' element allows for the use of a specific substance or pharmaceutical product, or a group or class of substances. In the case of an allergy or intolerance to a class of substances, (for example, "penicillins"), the 'reaction.substance' element could be used to code the specific substance that was identified as having caused the reaction (for example, "amoxycillin"). Duplication of the value in the 'code' and 'reaction.substance' elements is acceptable when a specific substance has been recorded in 'code'.
Binding
Strength
example
Description
Codes defining the type of the substance (including pharmaceutical products).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.substance.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.substance.CodeableConcept.coding.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
Comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should be an absolute reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.substance.CodeableConcept.coding.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
Definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.substance.CodeableConcept.coding.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
Definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.reaction.substance.CodeableConcept.coding.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.reaction.substance.CodeableConcept.coding.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.manifestation
Id
AllergyIntolerance.reaction.manifestation
Type
Cardinality
1 - *
Definition
Clinical symptoms and/or signs that are observed or associated with the adverse reaction event.
Comment
Manifestation can be expressed as a single word, phrase or brief description. For example: nausea, rash or no reaction. It is preferable that manifestation should be coded with a terminology, where possible. The values entered here may be used to display on an application screen as part of a list of adverse reactions, as recommended in the UK NHS CUI guidelines. Terminologies commonly used include, but are not limited to, SNOMED CT or ICD10.
Binding
Strength
example
Description
Clinical symptoms and/or signs that are observed or associated with an Adverse Reaction Event.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.manifestation.CodeableReference.concept
Id
CodeableReference.concept
Type
Cardinality
0 - 1
Definition
A reference to a concept - e.g. the information is identified by its general class to the degree of precision found in the terminology.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.manifestation.CodeableReference.concept.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.manifestation.CodeableReference.reference
Id
CodeableReference.reference
Type
Cardinality
0 - 1
Definition
A reference to a resource the provides exact details about the information being referenced.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.manifestation.CodeableReference.reference.Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.reaction.manifestation.CodeableReference.reference.Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.manifestation.CodeableReference.reference.Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.reaction.manifestation.CodeableReference.reference.Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.reaction.description
Id
AllergyIntolerance.reaction.description
Type
Cardinality
0 - 1
Definition
Text description about the reaction as a whole, including details of the manifestation if required.
Comment
Use the description to provide any details of a particular event of the occurred reaction such as circumstances, reaction specifics, what happened before/after. Information, related to the event, but not describing a particular care should be captured in the note field. For example: at the age of four, the patient was given penicillin for strep throat and subsequently developed severe hives.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.onset
Id
AllergyIntolerance.reaction.onset
Type
Cardinality
0 - 1
Definition
Record of the date and/or time of the onset of the Reaction.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.severity
Id
AllergyIntolerance.reaction.severity
Type
Cardinality
0 - 1
Definition
Clinical assessment of the severity of the reaction event as a whole, potentially considering multiple different manifestations.
Comment
It is acknowledged that this assessment is very subjective. There may be some specific practice domains where objective scales have been applied. Objective scales can be included in this model as extensions.
Binding
Strength
required
Description
Clinical assessment of the severity of a reaction event as a whole, potentially considering multiple different manifestations.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.exposureRoute
Id
AllergyIntolerance.reaction.exposureRoute
Type
Cardinality
0 - 1
Definition
Identification of the route by which the subject was exposed to the substance.
Comment
Coding of the route of exposure with a terminology should be used wherever possible.
Binding
Strength
example
Description
A coded concept describing the route or physiological path of exposure to a substance.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.exposureRoute.CodeableConcept.coding
Id
CodeableConcept.coding
Type
Cardinality
0 - *
Definition
A reference to a code defined by a terminology system.
Comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Requirements
Allows for alternative encodings within a code system, and translations to other code systems.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.exposureRoute.CodeableConcept.coding.Coding.system
Id
Coding.system
Type
Cardinality
0 - 1
Definition
The identification of the code system that defines the meaning of the symbol in the code.
Comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should be an absolute reference to some definition that establishes the system clearly and unambiguously.
Requirements
Need to be unambiguous about the source of the definition of the symbol.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.exposureRoute.CodeableConcept.coding.Coding.version
Id
Coding.version
Type
Cardinality
0 - 1
Definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.exposureRoute.CodeableConcept.coding.Coding.code
Id
Coding.code
Type
Cardinality
0 - 1
Definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Comment
Requirements
Need to refer to a particular code in the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.reaction.exposureRoute.CodeableConcept.coding.Coding.display
Id
Coding.display
Type
Cardinality
0 - 1
Definition
A representation of the meaning of the code in the system, following the rules of the system.
Comment
Requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cod-1
Path
AllergyIntolerance.reaction.exposureRoute.CodeableConcept.coding.Coding.userSelected
Id
Coding.userSelected
Type
Cardinality
0 - 1
Definition
Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.note
Id
AllergyIntolerance.reaction.note
Type
Cardinality
0 - *
Definition
Additional text about the adverse reaction event not captured in other fields.
Comment
Use this field to record information indirectly related to a particular event and not captured in the description. For example: Clinical records are no longer available, recorded based on information provided to the patient by her mother and her mother is deceased.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.note.Annotation.author[x]
Id
Annotation.author[x]
Type
Cardinality
0 - 1
Definition
The individual responsible for making the annotation.
Comment
Organization is used when there's no need for specific attribution as to who made the comment.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.note.Annotation.author[x].Reference.reference
Id
Reference.reference
Type
Cardinality
0 - 1
Definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.
Comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
ref-1
Path
AllergyIntolerance.reaction.note.Annotation.author[x].Reference.type
Id
Reference.type
Type
Cardinality
0 - 1
Definition
The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.
The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).
Comment
This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a known RESTful URL) or by resolving the target of the reference.
Binding
Strength
extensible
Description
Aa resource (or, for logical models, the URI of the logical model).
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
AllergyIntolerance.reaction.note.Annotation.author[x].Reference.identifier
Id
Reference.identifier
Type
Cardinality
0 - 1
Definition
An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.
Comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.
When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference
Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.
Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).
This element only allows for a single identifier. In the case where additional identifers are required, use the [http://hl7.org/fhir/StructureDefinition/additionalIdentifier](http://hl7.org/fhir/extensions/StructureDefinition-additionalIdentifier.html) extension.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.reaction.note.Annotation.author[x].Reference.display
Id
Reference.display
Type
Cardinality
0 - 1
Definition
Plain text narrative that identifies the resource in addition to the resource reference.
Comment
This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
ref-2
Path
AllergyIntolerance.reaction.note.Annotation.time
Id
Annotation.time
Type
Cardinality
0 - 1
Definition
Indicates when this particular annotation was made.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children