Summary
Diagnostics
Care Provision
Request & Response
Medications
Workflow
Entities
Management
Individuals
General
Billing
Support
Payment
Security
Other
Conformance
Documents
Terminology
Definitional Artifacts
Medication Definition
Evidence-Based Medicine
Quality Reporting & Testing
Public Health & Research
Complex
Primitive
ActivityDefinition
CapabilityStatement
ChargeItemDefinition
Claim
CodeSystem
Composition
ConceptMap
CoverageEligibilityRequest
Encounter
Group
Library
List
Measure
MedicinalProductDefinition
MessageHeader
NamingSystem
Observation
Patient
PlanDefinition
Resource
StructureDefinition
StructureMap
ValueSet
default
The header for a message exchange that is either requesting or responding to an action. The reference(s) that are the subject of the action as well as other information related to the action are typically transmitted in a bundle in which the MessageHeader resource instance is the first resource in the bundle.
MessageHeader
Path
MessageHeader
Id
MessageHeader
Cardinality
0 - *
Definition
The header for a message exchange that is either requesting or responding to an action. The reference(s) that are the subject of the action as well as other information related to the action are typically transmitted in a bundle in which the MessageHeader resource instance is the first resource in the bundle.
Comment
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
MessageHeader.event[x]
Id
MessageHeader.event[x]
Type
Cardinality
1 - 1
Definition
Code that identifies the event this message represents and connects it with its definition. Events defined as part of the FHIR specification have the system value "http://terminology.hl7.org/CodeSystem/message-events". Alternatively uri to the EventDefinition.
Comment
The time of the event will be found in the focus resource. The time of the message will be found in [Bundle.timestamp](bundle-definitions.html#Bundle.timestamp).
Requirements
Drives the behavior associated with this message.
Binding
Strength
example
Description
One of the message events defined as part of this version of FHIR.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.event[x].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 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
MessageHeader.event[x].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
MessageHeader.event[x].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
Path
MessageHeader.event[x].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
Path
MessageHeader.event[x].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
MessageHeader.destination
Id
MessageHeader.destination
Type
Cardinality
0 - *
Definition
The destination application which the message is intended for.
Comment
There SHOULD be at least one destination, but in some circumstances, the source system is unaware of any particular destination system.
Requirements
Indicates where message is to be sent for routing purposes. Allows verification of "am I the intended recipient".
Constraint
ele-1 [error]
All FHIR elements must have a @value or children unless an empty Parameters resource
Path
MessageHeader.destination.name
Id
MessageHeader.destination.name
Type
Cardinality
0 - 1
Definition
Human-readable name for the target system.
Comment
Requirements
May be used for routing of response and/or to support audit.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.target
Id
MessageHeader.destination.target
Type
Cardinality
0 - 1
Definition
Identifies the target end system in situations where the initial message transmission is to an intermediary system.
Comment
Requirements
Supports multi-hop routing.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.target.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-1
Path
MessageHeader.destination.target.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.target.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.target.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.target.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.target.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, a 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
MessageHeader.destination.target.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 [Rendered Value extension](extension-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
Path
MessageHeader.destination.target.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
MessageHeader.destination.target.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
MessageHeader.destination.target.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
Path
MessageHeader.destination.endpoint
Id
MessageHeader.destination.endpoint
Type
Cardinality
1 - 1
Definition
Indicates where the message should be routed to.
Comment
The id may be a non-resolvable URI for systems that do not use standard network-based addresses.
Requirements
Identifies where to route the message.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.receiver
Id
MessageHeader.destination.receiver
Type
Cardinality
0 - 1
Definition
Allows data conveyed by a message to be addressed to a particular person or department when routing to a specific application isn't sufficient.
Comment
Requirements
Allows routing beyond just the application level.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.receiver.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-1
Path
MessageHeader.destination.receiver.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.receiver.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.receiver.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.receiver.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.destination.receiver.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, a 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
MessageHeader.destination.receiver.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 [Rendered Value extension](extension-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
Path
MessageHeader.destination.receiver.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
MessageHeader.destination.receiver.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
MessageHeader.destination.receiver.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
Path
MessageHeader.sender
Id
MessageHeader.sender
Type
Cardinality
0 - 1
Definition
Identifies the sending system to allow the use of a trust relationship.
Comment
Use case is for where a (trusted) sending system is responsible for multiple organizations, and therefore cannot differentiate based on source endpoint / authentication alone.
Requirements
Allows routing beyond just the application level.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.sender.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-1
Path
MessageHeader.sender.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.sender.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.sender.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.sender.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.sender.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
MessageHeader.sender.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, a 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
MessageHeader.sender.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 [Rendered Value extension](extension-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
Path
MessageHeader.sender.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
MessageHeader.sender.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
MessageHeader.sender.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 high 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
MessageHeader.sender.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
MessageHeader.sender.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-1
Path
MessageHeader.sender.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.sender.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.sender.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
Path
MessageHeader.sender.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
Path
MessageHeader.enterer
Id
MessageHeader.enterer
Type
Cardinality
0 - 1
Definition
The person or device that performed the data entry leading to this message. When there is more than one candidate, pick the most proximal to the message. Can provide other enterers in extensions.
Comment
Usually only for the request but can be used in a response.
Requirements
Need to know for audit/traceback requirements and possibly for authorization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.enterer.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-1
Path
MessageHeader.enterer.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.enterer.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.enterer.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.enterer.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.enterer.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
MessageHeader.enterer.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, a 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
MessageHeader.enterer.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 [Rendered Value extension](extension-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
Path
MessageHeader.enterer.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
MessageHeader.enterer.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
MessageHeader.enterer.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 high 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
MessageHeader.enterer.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
MessageHeader.enterer.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-1
Path
MessageHeader.enterer.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.enterer.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.enterer.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
Path
MessageHeader.enterer.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
Path
MessageHeader.author
Id
MessageHeader.author
Type
Cardinality
0 - 1
Definition
The logical author of the message - the person or device that decided the described event should happen. When there is more than one candidate, pick the most proximal to the MessageHeader. Can provide other authors in extensions.
Comment
Usually only for the request but can be used in a response.
Requirements
Need to know for audit/traceback requirements and possibly for authorization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.author.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-1
Path
MessageHeader.author.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.author.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.author.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.author.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.author.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
MessageHeader.author.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, a 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
MessageHeader.author.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 [Rendered Value extension](extension-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
Path
MessageHeader.author.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
MessageHeader.author.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
MessageHeader.author.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 high 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
MessageHeader.author.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
MessageHeader.author.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-1
Path
MessageHeader.author.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.author.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.author.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
Path
MessageHeader.author.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
Path
MessageHeader.source
Id
MessageHeader.source
Type
Cardinality
1 - 1
Definition
The source application from which this message originated.
Comment
Requirements
Allows replies, supports audit.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children unless an empty Parameters resource
Path
MessageHeader.source.name
Id
MessageHeader.source.name
Type
Cardinality
0 - 1
Definition
Human-readable name for the source system.
Comment
Requirements
May be used to support audit.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.source.software
Id
MessageHeader.source.software
Type
Cardinality
0 - 1
Definition
May include configuration or other information useful in debugging.
Comment
Requirements
Supports audit and possibly interface engine behavior.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.source.version
Id
MessageHeader.source.version
Type
Cardinality
0 - 1
Definition
Can convey versions of multiple systems in situations where a message passes through multiple hands.
Comment
Requirements
Supports audit and possibly interface engine behavior.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.source.contact
Id
MessageHeader.source.contact
Type
Cardinality
0 - 1
Definition
An e-mail, phone, website or other contact point to use to resolve issues with message communications.
Comment
Requirements
Allows escalation of technical issues.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.source.contact.ContactPoint.system
Id
ContactPoint.system
Type
Cardinality
0 - 1
Definition
Telecommunications form for contact point - what communications system is required to make use of the contact.
Comment
Binding
Strength
required
Description
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Condition
cpt-2
Path
MessageHeader.source.contact.ContactPoint.value
Id
ContactPoint.value
Type
Cardinality
0 - 1
Definition
The actual contact point details, in a form that is meaningful to the designated communication system (i.e. phone number or email address).
Comment
Additional text data such as phone extension numbers, or notes about use of the contact are sometimes included in the value.
Requirements
Need to support legacy numbers that are not in a tightly controlled format.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.source.contact.ContactPoint.use
Id
ContactPoint.use
Type
Cardinality
0 - 1
Definition
Identifies the purpose for the contact point.
Comment
Applications can assume that a contact is current unless it explicitly says that it is temporary or old.
Requirements
Need to track the way a person uses this contact, so a user can choose which is appropriate for their purpose.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.source.contact.ContactPoint.rank
Id
ContactPoint.rank
Type
Cardinality
0 - 1
Definition
Specifies a preferred order in which to use a set of contacts. ContactPoints with lower rank values are more preferred than those with higher rank values.
Comment
Note that rank does not necessarily follow the order in which the contacts are represented in the instance.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.source.contact.ContactPoint.period
Id
ContactPoint.period
Type
Cardinality
0 - 1
Definition
Time period when the contact point was/is in use.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.source.contact.ContactPoint.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
MessageHeader.source.contact.ContactPoint.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 high 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
MessageHeader.source.endpoint
Id
MessageHeader.source.endpoint
Type
Cardinality
1 - 1
Definition
Identifies the routing target to send acknowledgements to.
Comment
The id may be a non-resolvable URI for systems that do not use standard network-based addresses.
Requirements
Identifies where to send responses, may influence security permissions.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.responsible
Id
MessageHeader.responsible
Type
Cardinality
0 - 1
Definition
The person or organization that accepts overall responsibility for the contents of the message. The implication is that the message event happened under the policies of the responsible party.
Comment
Usually only for the request but can be used in a response.
Requirements
Need to know for audit/traceback requirements and possibly for authorization.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.responsible.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-1
Path
MessageHeader.responsible.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.responsible.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.responsible.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.responsible.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.responsible.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
MessageHeader.responsible.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, a 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
MessageHeader.responsible.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 [Rendered Value extension](extension-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
Path
MessageHeader.responsible.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
MessageHeader.responsible.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
MessageHeader.responsible.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 high 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
MessageHeader.responsible.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
MessageHeader.responsible.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-1
Path
MessageHeader.responsible.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.responsible.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.responsible.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
Path
MessageHeader.responsible.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
Path
MessageHeader.reason
Id
MessageHeader.reason
Type
Cardinality
0 - 1
Definition
Coded indication of the cause for the event - indicates a reason for the occurrence of the event that is a focus of this message.
Comment
Requirements
Need to be able to track why resources are being changed and report in the audit log/history of the resource. May affect authorization.
Binding
Strength
example
Description
Reason for event occurrence.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.reason.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
MessageHeader.reason.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 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
MessageHeader.reason.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
MessageHeader.reason.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
Path
MessageHeader.reason.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
Path
MessageHeader.reason.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
MessageHeader.response
Id
MessageHeader.response
Type
Cardinality
0 - 1
Definition
Information about the message that this message is a response to. Only present if this message is a response.
Comment
Constraint
ele-1 [error]
All FHIR elements must have a @value or children unless an empty Parameters resource
Path
MessageHeader.response.identifier
Id
MessageHeader.response.identifier
Type
Cardinality
1 - 1
Definition
The MessageHeader.id of the message to which this message is a response.
Comment
Requirements
Allows receiver to know what message is being responded to.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.response.code
Id
MessageHeader.response.code
Type
Cardinality
1 - 1
Definition
Code that identifies the type of response to the message - whether it was successful or not, and whether it should be resent or not.
Comment
This is a generic response to the request message. Specific data for the response will be found in MessageHeader.focus.
Requirements
Allows the sender of the acknowledge message to know if the request was successful or if action is needed.
Binding
Strength
required
Description
The kind of response to a message.
ValueSet
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.response.details
Id
MessageHeader.response.details
Type
Cardinality
0 - 1
Definition
Full details of any issues found in the message.
Comment
This SHALL be contained in the bundle. If any of the issues are errors, the response code SHALL be an error.
Requirements
Allows the sender of the message to determine what the specific issues are.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.response.details.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-1
Path
MessageHeader.response.details.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.response.details.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.response.details.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.response.details.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.response.details.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, a 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
MessageHeader.response.details.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 [Rendered Value extension](extension-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
Path
MessageHeader.response.details.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
MessageHeader.response.details.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
MessageHeader.response.details.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
Path
MessageHeader.focus
Id
MessageHeader.focus
Type
Cardinality
0 - *
Definition
The actual data of the message - a reference to the root/focus class of the event.
Comment
The data is defined where the transaction type is defined. The transaction data is always included in the bundle that is the full message. Only the root resource is specified. The resources it references should be contained in the bundle but are not also listed here. Multiple repetitions are allowed to cater for merges and other situations with multiple focal targets.
Requirements
Every message event is about actual data, a single resource, that is identified in the definition of the event, and perhaps some or all linked resources.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.focus.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-1
Path
MessageHeader.focus.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.focus.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.focus.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.focus.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.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.focus.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
MessageHeader.focus.Reference.identifier.Identifier.system
Id
Identifier.system
Type
Cardinality
0 - 1
Definition
Establishes the namespace for the value - that is, a 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
MessageHeader.focus.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 [Rendered Value extension](extension-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
Path
MessageHeader.focus.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
MessageHeader.focus.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
MessageHeader.focus.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 high 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
MessageHeader.focus.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
MessageHeader.focus.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-1
Path
MessageHeader.focus.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 RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.focus.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).
Constraint
ele-1 [error]
All FHIR elements must have a @value or children
Path
MessageHeader.focus.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
Path
MessageHeader.focus.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
Path
MessageHeader.definition
Id
MessageHeader.definition
Type
Cardinality
0 - 1
Definition
Permanent link to the MessageDefinition for this message.
Comment
Requirements
Allows sender to define the expected contents of the message.
Constraint
ele-1 [error]
All FHIR elements must have a @value or children