HL7 PT FHIR Implementation Guide: Example IG Release 1 | STU1
1.0.0 - STU1 International flag

HL7 PT FHIR Implementation Guide: Example IG Release 1 | STU1, published by HL7 Portugal. This guide is not an authorized publication; it is the continuous build for version 1.0.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/hl7-pt/patient-admin-ig/ and changes regularly. See the Directory of published versions

Resource Profile: PTMessageHeader - Detailed Descriptions

Active as of 2025-09-26

Definitions for the MessageHeader-Pt resource profile.

Guidance on how to interpret the contents of this table can be foundhere

0. MessageHeader
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.

ShortA resource that describes a message that is exchanged between systems
Control0..*
Is Modifierfalse
Must Supportfalse
Summaryfalse
Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
dom-3: 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 (contained.where(((id.exists() and ('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url)))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(uri) = '#').exists()).not()).trace('unmatched', id).empty())
dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
dom-6: A resource should have narrative for robust management (text.`div`.exists())
2. MessageHeader.id
Definition

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

ShortLogical id of this artifact
Comments

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

Control10..1
Typeid
Is Modifierfalse
Must Supportfalse
Summarytrue
4. MessageHeader.meta
Definition

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

ShortMetadata about the resource
Control0..01
TypeMeta
Is Modifierfalse
Must Supportfalse
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
6. MessageHeader.implicitRules
Definition

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

ShortA set of rules under which this content was created
Comments

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

Control0..01
Typeuri
Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
8. MessageHeader.language
Definition

The base language in which the resource is written.

ShortLanguage of the resource content
Comments

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

Control0..01
BindingThe codes SHOULD be taken from CommonLanguageshttp://hl7.org/fhir/ValueSet/languages|4.3.0
(preferred to http://hl7.org/fhir/ValueSet/languages|4.3.0)

IETF language tag

Additional BindingsPurpose
AllLanguagesMax Binding
Typecode
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summaryfalse
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
10. MessageHeader.text
Definition

A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

ShortText summary of the resource, for human interpretation
Comments

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

Control0..01
TypeNarrative
Is Modifierfalse
Must Supportfalse
Summaryfalse
Alternate Namesnarrative, html, xhtml, display
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
12. MessageHeader.contained
Definition

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

ShortContained, inline Resources
Comments

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

Control0..0*
TypeResource
Is Modifierfalse
Must Supportfalse
Summaryfalse
Alternate Namesinline resources, anonymous resources, contained resources
Invariantsdom-r4b: Containing new R4B resources within R4 resources may cause interoperability issues if instances are shared with R4 systems (($this is Citation or $this is Evidence or $this is EvidenceReport or $this is EvidenceVariable or $this is MedicinalProductDefinition or $this is PackagedProductDefinition or $this is AdministrableProductDefinition or $this is Ingredient or $this is ClinicalUseDefinition or $this is RegulatedAuthorization or $this is SubstanceDefinition or $this is SubscriptionStatus or $this is SubscriptionTopic) implies (%resource is Citation or %resource is Evidence or %resource is EvidenceReport or %resource is EvidenceVariable or %resource is MedicinalProductDefinition or %resource is PackagedProductDefinition or %resource is AdministrableProductDefinition or %resource is Ingredient or %resource is ClinicalUseDefinition or %resource is RegulatedAuthorization or %resource is SubstanceDefinition or %resource is SubscriptionStatus or %resource is SubscriptionTopic))
dom-r4b: Containing new R4B resources within R4 resources may cause interoperability issues if instances are shared with R4 systems (($this is Citation or $this is Evidence or $this is EvidenceReport or $this is EvidenceVariable or $this is MedicinalProductDefinition or $this is PackagedProductDefinition or $this is AdministrableProductDefinition or $this is Ingredient or $this is ClinicalUseDefinition or $this is RegulatedAuthorization or $this is SubstanceDefinition or $this is SubscriptionStatus or $this is SubscriptionTopic) implies (%resource is Citation or %resource is Evidence or %resource is EvidenceReport or %resource is EvidenceVariable or %resource is MedicinalProductDefinition or %resource is PackagedProductDefinition or %resource is AdministrableProductDefinition or %resource is Ingredient or %resource is ClinicalUseDefinition or %resource is RegulatedAuthorization or %resource is SubstanceDefinition or %resource is SubscriptionStatus or %resource is SubscriptionTopic))
14. MessageHeader.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

ShortExtensions that cannot be ignored
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Control0..*
TypeExtension
Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
Must Supportfalse
Summaryfalse
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
16. MessageHeader.event[x]
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.

ShortCode for the event this message represents or link to event definition
Comments

The time of the event will be found in the focus resource. The time of the message will be found in Bundle.timestamp.


The time of the event will be found in the focus resource. The time of the message will be found in Bundle.timestamp.

Control1..1
BindingFor example codes, see MessageEventhttp://hl7.org/fhir/ValueSet/message-events|4.3.0
(example to http://hl7.org/fhir/ValueSet/message-events|4.3.0)

One of the message events defined as part of this version of FHIR.

TypeCoding, uri
[x] NoteSeeChoice of Data Typesfor further information about how to use [x]
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Drives the behavior associated with this message.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
18. MessageHeader.author
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.

ShortThe source of the decision
Comments

Usually only for the request but can be used in a response.

Control0..01
TypeReference(Practitioner, PractitionerRole)
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Need to know for audit/traceback requirements and possibly for authorization.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
20. MessageHeader.source
Definition

The source application from which this message originated.

ShortMessage source application
Control1..1
TypeBackboneElement
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Allows replies, supports audit.

Invariantsele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (hasValue() or (children().count() > id.count()) or $this is Parameters)
22. MessageHeader.source.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

ShortExtensions that cannot be ignored even if unrecognized
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Control0..*
TypeExtension
Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
Summarytrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
24. MessageHeader.source.software
Definition

May include configuration or other information useful in debugging.

ShortName of software running the system
Control0..01
Typestring
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summarytrue
Requirements

Supports audit and possibly interface engine behavior.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
26. MessageHeader.source.version
Definition

Can convey versions of multiple systems in situations where a message passes through multiple hands.

ShortVersion of software running
NoteThis is a business version Id, not a resource version Id (see discussion)
Control0..01
Typestring
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summarytrue
Requirements

Supports audit and possibly interface engine behavior.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
28. MessageHeader.source.contact
Definition

An e-mail, phone, website or other contact point to use to resolve issues with message communications.

ShortHuman contact for problems
Control0..01
TypeContactPoint
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Allows escalation of technical issues.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
30. MessageHeader.source.endpoint
Definition

Identifies the routing target to send acknowledgements to.

ShortActual message source address or id
Comments

The id may be a non-resolvable URI for systems that do not use standard network-based addresses.

Control1..1
Typeurl
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summarytrue
Requirements

Identifies where to send responses, may influence security permissions.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
32. MessageHeader.responsible
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.

ShortFinal responsibility for event
Comments

Usually only for the request but can be used in a response.

Control0..01
TypeReference(Practitioner, PractitionerRole, Organization)
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Need to know for audit/traceback requirements and possibly for authorization.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
34. MessageHeader.reason
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.

ShortCause of event
Control0..01
BindingFor example codes, see ExampleMessageReasonCodeshttp://hl7.org/fhir/ValueSet/message-reason-encounter|4.3.0
(example to http://hl7.org/fhir/ValueSet/message-reason-encounter|4.3.0)

Reason for event occurrence.

TypeCodeableConcept
Is Modifierfalse
Must Supportfalse
Summarytrue
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.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
36. MessageHeader.definition
Definition

Permanent link to the MessageDefinition for this message.

ShortLink to the definition for this message
Control0..01
Typecanonical(MessageDefinition)
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summarytrue
Requirements

Allows sender to define the expected contents of the message.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))

Guidance on how to interpret the contents of this table can be foundhere

0. MessageHeader
2. MessageHeader.id
Control1..?
4. MessageHeader.meta
Control0..0
6. MessageHeader.implicitRules
Control0..0
8. MessageHeader.language
Control0..0
10. MessageHeader.text
Control0..0
12. MessageHeader.contained
Control0..0
14. MessageHeader.event[x]
TypeCoding, uri
[x] NoteSeeChoice of Data Typesfor further information about how to use [x]
16. MessageHeader.destination
18. MessageHeader.destination.target
Control0..0
20. MessageHeader.destination.receiver
22. MessageHeader.destination.receiver.type
Control0..0
24. MessageHeader.destination.receiver.identifier
NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..0
26. MessageHeader.destination.receiver.display
Control0..0
28. MessageHeader.sender
30. MessageHeader.sender.type
Control0..0
32. MessageHeader.sender.identifier
NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..0
34. MessageHeader.sender.display
Control0..0
36. MessageHeader.enterer
38. MessageHeader.enterer.type
Control0..0
40. MessageHeader.enterer.identifier
NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..0
42. MessageHeader.enterer.display
Control0..0
44. MessageHeader.author
Control0..0
46. MessageHeader.source
48. MessageHeader.source.software
Control0..0
50. MessageHeader.source.version
NoteThis is a business version Id, not a resource version Id (see discussion)
Control0..0
52. MessageHeader.source.contact
Control0..0
54. MessageHeader.responsible
Control0..0
56. MessageHeader.reason
Control0..0
58. MessageHeader.focus
60. MessageHeader.focus.type
Control0..0
62. MessageHeader.focus.identifier
NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..0
64. MessageHeader.focus.display
Control0..0
66. MessageHeader.definition
Control0..0

Guidance on how to interpret the contents of this table can be foundhere

0. MessageHeader
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.

ShortA resource that describes a message that is exchanged between systems
Control0..*
Is Modifierfalse
Must Supportfalse
Summaryfalse
Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
dom-3: 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 (contained.where(((id.exists() and ('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url)))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(uri) = '#').exists()).not()).trace('unmatched', id).empty())
dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
dom-6: A resource should have narrative for robust management (text.`div`.exists())
2. MessageHeader.id
Definition

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

ShortLogical id of this artifact
Comments

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

Control1..1
Typeid
Is Modifierfalse
Must Supportfalse
Summarytrue
4. MessageHeader.meta
Definition

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

ShortMetadata about the resource
Control0..0
TypeMeta
Is Modifierfalse
Must Supportfalse
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
6. MessageHeader.implicitRules
Definition

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

ShortA set of rules under which this content was created
Comments

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

Control0..0
Typeuri
Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
8. MessageHeader.language
Definition

The base language in which the resource is written.

ShortLanguage of the resource content
Comments

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

Control0..0
BindingThe codes SHOULD be taken from CommonLanguages
(preferred to http://hl7.org/fhir/ValueSet/languages|4.3.0)

IETF language tag

Additional BindingsPurpose
AllLanguagesMax Binding
Typecode
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summaryfalse
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
10. MessageHeader.text
Definition

A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

ShortText summary of the resource, for human interpretation
Comments

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

Control0..0
TypeNarrative
Is Modifierfalse
Must Supportfalse
Summaryfalse
Alternate Namesnarrative, html, xhtml, display
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
12. MessageHeader.contained
Definition

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

ShortContained, inline Resources
Comments

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

Control0..0
TypeResource
Is Modifierfalse
Must Supportfalse
Summaryfalse
Alternate Namesinline resources, anonymous resources, contained resources
Invariantsdom-r4b: Containing new R4B resources within R4 resources may cause interoperability issues if instances are shared with R4 systems (($this is Citation or $this is Evidence or $this is EvidenceReport or $this is EvidenceVariable or $this is MedicinalProductDefinition or $this is PackagedProductDefinition or $this is AdministrableProductDefinition or $this is Ingredient or $this is ClinicalUseDefinition or $this is RegulatedAuthorization or $this is SubstanceDefinition or $this is SubscriptionStatus or $this is SubscriptionTopic) implies (%resource is Citation or %resource is Evidence or %resource is EvidenceReport or %resource is EvidenceVariable or %resource is MedicinalProductDefinition or %resource is PackagedProductDefinition or %resource is AdministrableProductDefinition or %resource is Ingredient or %resource is ClinicalUseDefinition or %resource is RegulatedAuthorization or %resource is SubstanceDefinition or %resource is SubscriptionStatus or %resource is SubscriptionTopic))
14. MessageHeader.extension
Definition

May be used to represent additional information that is not part of the basic definition of the resource. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

ShortAdditional content defined by implementations
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Control0..*
TypeExtension
Is Modifierfalse
Must Supportfalse
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
16. MessageHeader.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

ShortExtensions that cannot be ignored
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Control0..*
TypeExtension
Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
Must Supportfalse
Summaryfalse
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
18. MessageHeader.event[x]
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.

ShortCode for the event this message represents or link to event definition
Comments

The time of the event will be found in the focus resource. The time of the message will be found in Bundle.timestamp.

Control1..1
BindingFor example codes, see MessageEvent
(example to http://hl7.org/fhir/ValueSet/message-events|4.3.0)

One of the message events defined as part of this version of FHIR.

TypeCoding
[x] NoteSeeChoice of Data Typesfor further information about how to use [x]
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Drives the behavior associated with this message.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
20. MessageHeader.destination
Definition

The destination application which the message is intended for.

ShortMessage destination application(s)
Comments

There SHOULD be at least one destination, but in some circumstances, the source system is unaware of any particular destination system.

Control0..*
TypeBackboneElement
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Indicates where message is to be sent for routing purposes. Allows verification of "am I the intended recipient".

Invariantsele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (hasValue() or (children().count() > id.count()) or $this is Parameters)
22. MessageHeader.destination.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

ShortUnique id for inter-element referencing
Control0..1
Typestring
Is Modifierfalse
XML FormatIn the XML format, this property is represented as an attribute.
Summaryfalse
24. MessageHeader.destination.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

ShortAdditional content defined by implementations
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Control0..*
TypeExtension
Is Modifierfalse
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
26. MessageHeader.destination.modifierExtension
Definition

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

ShortExtensions that cannot be ignored even if unrecognized
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Control0..*
TypeExtension
Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
Summarytrue
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content, modifiers
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
28. MessageHeader.destination.name
Definition

Human-readable name for the target system.

ShortName of system
Control0..1
Typestring
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summarytrue
Requirements

May be used for routing of response and/or to support audit.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
30. MessageHeader.destination.target
Definition

Identifies the target end system in situations where the initial message transmission is to an intermediary system.

ShortParticular delivery destination within the destination
Control0..0
TypeReference(Device)
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Supports multi-hop routing.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
32. MessageHeader.destination.endpoint
Definition

Indicates where the message should be routed to.

ShortActual destination address or id
Comments

The id may be a non-resolvable URI for systems that do not use standard network-based addresses.

Control1..1
Typeurl
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supportfalse
Summarytrue
Requirements

Identifies where to route the message.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
34. MessageHeader.destination.receiver
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.

ShortIntended "real-world" recipient for the data
Control0..1
TypeReference(Practitioner, PractitionerRole, Organization)
Is Modifierfalse
Must Supportfalse
Summarytrue
Requirements

Allows routing beyond just the application level.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
36. MessageHeader.destination.receiver.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

ShortUnique id for inter-element referencing
Control0..1
Typeid
Is Modifierfalse
XML FormatIn the XML format, this property is represented as an attribute.
Summaryfalse
38. MessageHeader.destination.receiver.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

ShortAdditional content defined by implementations
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Control0..*
TypeExtension
Is Modifierfalse
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
SlicingThis element introduces a set of slices on MessageHeader.destination.receiver.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ url
  • 40. MessageHeader.destination.receiver.reference
    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.

    ShortLiteral reference, Relative, internal or absolute URL
    Comments

    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.

    Control0..1
    This element is affected by the following invariants: ref-1
    Typestring
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    42. MessageHeader.destination.receiver.type
    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).

    ShortType the reference refers to (e.g. "Patient")
    Comments

    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.

    Control0..0
    BindingUnless not suitable, these codes SHALL be taken from ResourceType
    (extensible to http://hl7.org/fhir/ValueSet/resource-types|4.3.0)
    Typeuri
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    44. MessageHeader.destination.receiver.identifier
    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.

    ShortLogical reference, when literal reference is not known
    Comments

    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).

    NoteThis is a business identifier, not a resource identifier (see discussion)
    Control0..0
    TypeIdentifier
    Is Modifierfalse
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    46. MessageHeader.destination.receiver.display
    Definition

    Plain text narrative that identifies the resource in addition to the resource reference.

    ShortText alternative for the resource
    Comments

    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.

    Control0..0
    Typestring
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    48. MessageHeader.sender
    Definition

    Identifies the sending system to allow the use of a trust relationship.

    ShortReal world sender of the message
    Comments

    Use case is for where a (trusted) sending system is responsible for multiple organizations, and therefore cannot differentiate based on source endpoint / authentication alone.

    Control0..1
    TypeReference(Practitioner, PractitionerRole, Organization)
    Is Modifierfalse
    Must Supportfalse
    Summarytrue
    Requirements

    Allows routing beyond just the application level.

    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    50. MessageHeader.sender.id
    Definition

    Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

    ShortUnique id for inter-element referencing
    Control0..1
    Typeid
    Is Modifierfalse
    XML FormatIn the XML format, this property is represented as an attribute.
    Summaryfalse
    52. MessageHeader.sender.extension
    Definition

    May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

    ShortAdditional content defined by implementations
    Comments

    There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

    Control0..*
    TypeExtension
    Is Modifierfalse
    Summaryfalse
    Alternate Namesextensions, user content
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    SlicingThis element introduces a set of slices on MessageHeader.sender.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • value @ url
    • 54. MessageHeader.sender.reference
      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.

      ShortLiteral reference, Relative, internal or absolute URL
      Comments

      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.

      Control0..1
      This element is affected by the following invariants: ref-1
      Typestring
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      56. MessageHeader.sender.type
      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).

      ShortType the reference refers to (e.g. "Patient")
      Comments

      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.

      Control0..0
      BindingUnless not suitable, these codes SHALL be taken from ResourceType
      (extensible to http://hl7.org/fhir/ValueSet/resource-types|4.3.0)
      Typeuri
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      58. MessageHeader.sender.identifier
      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.

      ShortLogical reference, when literal reference is not known
      Comments

      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).

      NoteThis is a business identifier, not a resource identifier (see discussion)
      Control0..0
      TypeIdentifier
      Is Modifierfalse
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      60. MessageHeader.sender.display
      Definition

      Plain text narrative that identifies the resource in addition to the resource reference.

      ShortText alternative for the resource
      Comments

      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.

      Control0..0
      Typestring
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      62. MessageHeader.enterer
      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.

      ShortThe source of the data entry
      Comments

      Usually only for the request but can be used in a response.

      Control0..1
      TypeReference(Practitioner, PractitionerRole)
      Is Modifierfalse
      Must Supportfalse
      Summarytrue
      Requirements

      Need to know for audit/traceback requirements and possibly for authorization.

      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      64. MessageHeader.enterer.id
      Definition

      Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

      ShortUnique id for inter-element referencing
      Control0..1
      Typeid
      Is Modifierfalse
      XML FormatIn the XML format, this property is represented as an attribute.
      Summaryfalse
      66. MessageHeader.enterer.extension
      Definition

      May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

      ShortAdditional content defined by implementations
      Comments

      There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

      Control0..*
      TypeExtension
      Is Modifierfalse
      Summaryfalse
      Alternate Namesextensions, user content
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      SlicingThis element introduces a set of slices on MessageHeader.enterer.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
      • value @ url
      • 68. MessageHeader.enterer.reference
        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.

        ShortLiteral reference, Relative, internal or absolute URL
        Comments

        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.

        Control0..1
        This element is affected by the following invariants: ref-1
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        70. MessageHeader.enterer.type
        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).

        ShortType the reference refers to (e.g. "Patient")
        Comments

        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.

        Control0..0
        BindingUnless not suitable, these codes SHALL be taken from ResourceType
        (extensible to http://hl7.org/fhir/ValueSet/resource-types|4.3.0)
        Typeuri
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        72. MessageHeader.enterer.identifier
        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.

        ShortLogical reference, when literal reference is not known
        Comments

        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).

        NoteThis is a business identifier, not a resource identifier (see discussion)
        Control0..0
        TypeIdentifier
        Is Modifierfalse
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        74. MessageHeader.enterer.display
        Definition

        Plain text narrative that identifies the resource in addition to the resource reference.

        ShortText alternative for the resource
        Comments

        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.

        Control0..0
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        76. MessageHeader.author
        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.

        ShortThe source of the decision
        Comments

        Usually only for the request but can be used in a response.

        Control0..0
        TypeReference(Practitioner, PractitionerRole)
        Is Modifierfalse
        Must Supportfalse
        Summarytrue
        Requirements

        Need to know for audit/traceback requirements and possibly for authorization.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        78. MessageHeader.source
        Definition

        The source application from which this message originated.

        ShortMessage source application
        Control1..1
        TypeBackboneElement
        Is Modifierfalse
        Must Supportfalse
        Summarytrue
        Requirements

        Allows replies, supports audit.

        Invariantsele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (hasValue() or (children().count() > id.count()) or $this is Parameters)
        80. MessageHeader.source.id
        Definition

        Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

        ShortUnique id for inter-element referencing
        Control0..1
        Typestring
        Is Modifierfalse
        XML FormatIn the XML format, this property is represented as an attribute.
        Summaryfalse
        82. MessageHeader.source.extension
        Definition

        May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

        ShortAdditional content defined by implementations
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        84. MessageHeader.source.modifierExtension
        Definition

        May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

        Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

        ShortExtensions that cannot be ignored even if unrecognized
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
        Summarytrue
        Requirements

        Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

        Alternate Namesextensions, user content, modifiers
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        86. MessageHeader.source.name
        Definition

        Human-readable name for the source system.

        ShortName of system
        Control0..1
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supportfalse
        Summarytrue
        Requirements

        May be used to support audit.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        88. MessageHeader.source.software
        Definition

        May include configuration or other information useful in debugging.

        ShortName of software running the system
        Control0..0
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supportfalse
        Summarytrue
        Requirements

        Supports audit and possibly interface engine behavior.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        90. MessageHeader.source.version
        Definition

        Can convey versions of multiple systems in situations where a message passes through multiple hands.

        ShortVersion of software running
        NoteThis is a business version Id, not a resource version Id (see discussion)
        Control0..0
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supportfalse
        Summarytrue
        Requirements

        Supports audit and possibly interface engine behavior.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        92. MessageHeader.source.contact
        Definition

        An e-mail, phone, website or other contact point to use to resolve issues with message communications.

        ShortHuman contact for problems
        Control0..0
        TypeContactPoint
        Is Modifierfalse
        Must Supportfalse
        Summarytrue
        Requirements

        Allows escalation of technical issues.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        94. MessageHeader.source.endpoint
        Definition

        Identifies the routing target to send acknowledgements to.

        ShortActual message source address or id
        Comments

        The id may be a non-resolvable URI for systems that do not use standard network-based addresses.

        Control1..1
        Typeurl
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supportfalse
        Summarytrue
        Requirements

        Identifies where to send responses, may influence security permissions.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        96. MessageHeader.responsible
        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.

        ShortFinal responsibility for event
        Comments

        Usually only for the request but can be used in a response.

        Control0..0
        TypeReference(Practitioner, PractitionerRole, Organization)
        Is Modifierfalse
        Must Supportfalse
        Summarytrue
        Requirements

        Need to know for audit/traceback requirements and possibly for authorization.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        98. MessageHeader.reason
        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.

        ShortCause of event
        Control0..0
        BindingFor example codes, see ExampleMessageReasonCodes
        (example to http://hl7.org/fhir/ValueSet/message-reason-encounter|4.3.0)

        Reason for event occurrence.

        TypeCodeableConcept
        Is Modifierfalse
        Must Supportfalse
        Summarytrue
        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.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        100. MessageHeader.response
        Definition

        Information about the message that this message is a response to. Only present if this message is a response.

        ShortIf this is a reply to prior message
        Control0..1
        TypeBackboneElement
        Is Modifierfalse
        Must Supportfalse
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children unless an empty Parameters resource (hasValue() or (children().count() > id.count()) or $this is Parameters)
        102. MessageHeader.response.id
        Definition

        Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

        ShortUnique id for inter-element referencing
        Control0..1
        Typestring
        Is Modifierfalse
        XML FormatIn the XML format, this property is represented as an attribute.
        Summaryfalse
        104. MessageHeader.response.extension
        Definition

        May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

        ShortAdditional content defined by implementations
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        106. MessageHeader.response.modifierExtension
        Definition

        May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

        Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

        ShortExtensions that cannot be ignored even if unrecognized
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
        Summarytrue
        Requirements

        Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

        Alternate Namesextensions, user content, modifiers
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        108. MessageHeader.response.identifier
        Definition

        The MessageHeader.id of the message to which this message is a response.

        ShortId of original message
        NoteThis is a business identifier, not a resource identifier (see discussion)
        Control1..1
        Typeid
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supportfalse
        Summarytrue
        Requirements

        Allows receiver to know what message is being responded to.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        110. MessageHeader.response.code
        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.

        Shortok | transient-error | fatal-error
        Comments

        This is a generic response to the request message. Specific data for the response will be found in MessageHeader.focus.

        Control1..1
        BindingThe codes SHALL be taken from ResponseType
        (required to http://hl7.org/fhir/ValueSet/response-code|4.3.0)

        The kind of response to a message.

        Typecode
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supportfalse
        Summarytrue
        Requirements

        Allows the sender of the acknowledge message to know if the request was successful or if action is needed.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        112. MessageHeader.response.details
        Definition

        Full details of any issues found in the message.

        ShortSpecific list of hints/warnings/errors
        Comments

        This SHALL be contained in the bundle. If any of the issues are errors, the response code SHALL be an error.

        Control0..1
        TypeReference(OperationOutcome)
        Is Modifierfalse
        Must Supportfalse
        Summarytrue
        Requirements

        Allows the sender of the message to determine what the specific issues are.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        114. MessageHeader.focus
        Definition

        The actual data of the message - a reference to the root/focus class of the event.

        ShortThe actual content of the message
        Comments

        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.

        Control0..*
        TypeReference(Resource)
        Is Modifierfalse
        Must Supportfalse
        Summarytrue
        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.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        116. MessageHeader.focus.id
        Definition

        Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

        ShortUnique id for inter-element referencing
        Control0..1
        Typeid
        Is Modifierfalse
        XML FormatIn the XML format, this property is represented as an attribute.
        Summaryfalse
        118. MessageHeader.focus.extension
        Definition

        May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

        ShortAdditional content defined by implementations
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        SlicingThis element introduces a set of slices on MessageHeader.focus.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
        • value @ url
        • 120. MessageHeader.focus.reference
          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.

          ShortLiteral reference, Relative, internal or absolute URL
          Comments

          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.

          Control0..1
          This element is affected by the following invariants: ref-1
          Typestring
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Summarytrue
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          122. MessageHeader.focus.type
          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).

          ShortType the reference refers to (e.g. "Patient")
          Comments

          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.

          Control0..0
          BindingUnless not suitable, these codes SHALL be taken from ResourceType
          (extensible to http://hl7.org/fhir/ValueSet/resource-types|4.3.0)
          Typeuri
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Summarytrue
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          124. MessageHeader.focus.identifier
          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.

          ShortLogical reference, when literal reference is not known
          Comments

          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).

          NoteThis is a business identifier, not a resource identifier (see discussion)
          Control0..0
          TypeIdentifier
          Is Modifierfalse
          Summarytrue
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          126. MessageHeader.focus.display
          Definition

          Plain text narrative that identifies the resource in addition to the resource reference.

          ShortText alternative for the resource
          Comments

          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.

          Control0..0
          Typestring
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Summarytrue
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          128. MessageHeader.definition
          Definition

          Permanent link to the MessageDefinition for this message.

          ShortLink to the definition for this message
          Control0..0
          Typecanonical(MessageDefinition)
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Must Supportfalse
          Summarytrue
          Requirements

          Allows sender to define the expected contents of the message.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))