Attachment Reference Exchange (ARex)
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Attachment Reference Exchange (ARex) - Local Development build (v0.1.0) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions

Resource Profile: ARex Content Entry ( Experimental )

Official URL: https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-content-entry Version: 0.1.0
Draft as of 2026-08-12 Computable Name: ARexContentEntry

Metadata for a single retrievable content object. One entry describes exactly one object; this granularity is what allows a receiver to plan transfers against its own size ceiling rather than requiring the sender to fragment.

Usages:

You can also check for usages in the FHIR IG Statistics

Formal Views of Profile Content

Description of Profiles, Differentials, Snapshots and how the different presentations work.

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. DocumentReference C 0..* DocumentReference A reference to a document
Constraints: arex-ent-1
... implicitRules ?!Σ 0..1 uri A set of rules under which this content was created
... modifierExtension ?! 0..* Extension Extensions that cannot be ignored
... masterIdentifier SΣ 0..1 Identifier Master Version Specific Identifier
... status ?!Σ 1..1 code current | superseded | entered-in-error
Binding: DocumentReferenceStatus (required): The status of the document reference.
Fixed Value: current
... type SΣ 1..1 CodeableConcept Document type; LOINC document or attachment code where one applies
Binding: DocumentTypeValueSet (preferred): Precise type of clinical document.
... subject SΣ 1..1 Reference(Patient) Who/what is the subject of the document
... date SΣ 1..1 instant When this document reference was created
... content SΣ 1..1 BackboneElement Exactly one content object per entry
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... attachment Σ 1..1 Attachment Where to access the document
..... Slices for extension 1..* Extension Extension
Slice: Unordered, Open by value:url
...... extension:digest S 1..1 (Complex) ARex Digest
URL: https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest
..... contentType SΣ 1..1 code Mime type of the content, with charset etc.
Binding: Mime Types (required): The mime type of an attachment. Any valid mime type is allowed.
Example General: text/plain; charset=UTF-8, image/png
..... url SΣ 1..1 url Uri where the data can be found
Example General: http://www.acme.com/logo-small.png
..... size SΣ 1..1 unsignedInt Octet count as served, declared before retrieval
..... title SΣ 0..1 string Label to display in place of the data
Example General: Official Corporate Logo
.... format SΣ 0..1 Coding Format/content rules for the document
Binding: DocumentReferenceFormatCodeSet (preferred): Document Format Codes.
... context Σ 0..1 BackboneElement Clinical context of document
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... related S 0..* Reference(Resource) The governing transaction resource this content supports

doco Documentation for this format

Terminology Bindings

Path Status Usage ValueSet Version Source
DocumentReference.status Base required DocumentReferenceStatus 📍4.0.1 FHIR Std.
DocumentReference.type Base preferred Document Type Value Set 📍4.0.1 FHIR Std.
DocumentReference.content.​attachment.contentType Base required MimeType 📍4.0.1 FHIR Std.
DocumentReference.content.​format Base preferred DocumentReference Format Code Set 📍4.0.1 FHIR Std.

Constraints

Id Grade Path(s) Description Expression
arex-ent-1 error DocumentReference Content SHALL be referenced by an absolute URL, never embedded. content.attachment.url.exists() and content.attachment.url.startsWith('http')

This structure is derived from DocumentReference

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. DocumentReference C 0..* DocumentReference A reference to a document
Constraints: arex-ent-1
... masterIdentifier S 0..1 Identifier Master Version Specific Identifier
... identifier S 0..* Identifier Other identifiers for the document
... status 1..1 code current | superseded | entered-in-error
Fixed Value: current
... subject S 1..1 Reference(Patient) Who/what is the subject of the document
... date S 1..1 instant When this document reference was created
... content S 1..1 BackboneElement Exactly one content object per entry
.... attachment
..... extension 1..* Extension Extension
..... Slices for extension Content/Rules for all slices
...... extension:digest S 1..1 (Complex) ARex Digest
URL: https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest
..... contentType S 1..1 code Mime type of the content, with charset etc.
..... data 0..0 Prohibited. ARex exists to keep content out of the transaction payload.
..... url S 1..1 url Uri where the data can be found
..... size S 1..1 unsignedInt Octet count as served, declared before retrieval
..... hash 0..0 Prohibited. Attachment.hash is SHA-1 in R4; use the ARex Digest extension.
..... title S 0..1 string Label to display in place of the data
.... format S 0..1 Coding Format/content rules for the document
... context
.... related S 0..* Reference(Resource) The governing transaction resource this content supports

doco Documentation for this format

Constraints

Id Grade Path(s) Description Expression
arex-ent-1 error DocumentReference Content SHALL be referenced by an absolute URL, never embedded. content.attachment.url.exists() and content.attachment.url.startsWith('http')
NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. DocumentReference C 0..* DocumentReference A reference to a document
Constraints: arex-ent-1
... id Σ 0..1 id Logical id of this artifact
... meta Σ 0..1 Meta Metadata about the resource
... implicitRules ?!Σ 0..1 uri A set of rules under which this content was created
... text 0..1 Narrative Text summary of the resource, for human interpretation
This profile does not constrain the narrative in regard to content, language, or traceability to data elements
... contained 0..* Resource Contained, inline Resources
... extension 0..* Extension Additional content defined by implementations
... modifierExtension ?! 0..* Extension Extensions that cannot be ignored
... masterIdentifier SΣ 0..1 Identifier Master Version Specific Identifier
... identifier SΣ 0..* Identifier Other identifiers for the document
... status ?!Σ 1..1 code current | superseded | entered-in-error
Binding: DocumentReferenceStatus (required): The status of the document reference.
Fixed Value: current
... docStatus Σ 0..1 code preliminary | final | amended | entered-in-error
Binding: CompositionStatus (required): Status of the underlying document.
... type SΣ 1..1 CodeableConcept Document type; LOINC document or attachment code where one applies
Binding: DocumentTypeValueSet (preferred): Precise type of clinical document.
... category Σ 0..* CodeableConcept Categorization of document
Binding: DocumentClassValueSet (example): High-level kind of a clinical document at a macro level.
... subject SΣ 1..1 Reference(Patient) Who/what is the subject of the document
... date SΣ 1..1 instant When this document reference was created
... author Σ 0..* Reference(Practitioner | PractitionerRole | Organization | Device | Patient | RelatedPerson) Who and/or what authored the document
... authenticator 0..1 Reference(Practitioner | PractitionerRole | Organization) Who/what authenticated the document
... custodian 0..1 Reference(Organization) Organization which maintains the document
... relatesTo Σ 0..* BackboneElement Relationships to other documents
.... id 0..1 string Unique id for inter-element referencing
.... extension 0..* Extension Additional content defined by implementations
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... code Σ 1..1 code replaces | transforms | signs | appends
Binding: DocumentRelationshipType (required): The type of relationship between documents.
.... target Σ 1..1 Reference(DocumentReference) Target of the relationship
... description Σ 0..1 string Human-readable description
... securityLabel Σ 0..* CodeableConcept Document security-tags
Binding: All Security Labels (extensible): Security Labels from the Healthcare Privacy and Security Classification System.
... content SΣ 1..1 BackboneElement Exactly one content object per entry
.... id 0..1 string Unique id for inter-element referencing
.... extension 0..* Extension Additional content defined by implementations
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... attachment Σ 1..1 Attachment Where to access the document
..... id 0..1 string Unique id for inter-element referencing
..... Slices for extension 1..* Extension Extension
Slice: Unordered, Open by value:url
...... extension:digest S 1..1 (Complex) ARex Digest
URL: https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest
..... contentType SΣ 1..1 code Mime type of the content, with charset etc.
Binding: Mime Types (required): The mime type of an attachment. Any valid mime type is allowed.
Example General: text/plain; charset=UTF-8, image/png
..... language Σ 0..1 code Human language of the content (BCP-47)
Binding: CommonLanguages (preferred): A human language.
Additional BindingsPurpose
AllLanguages Max Binding

Example General: en-AU
..... url SΣ 1..1 url Uri where the data can be found
Example General: http://www.acme.com/logo-small.png
..... size SΣ 1..1 unsignedInt Octet count as served, declared before retrieval
..... title SΣ 0..1 string Label to display in place of the data
Example General: Official Corporate Logo
..... creation Σ 0..1 dateTime Date attachment was first created
.... format SΣ 0..1 Coding Format/content rules for the document
Binding: DocumentReferenceFormatCodeSet (preferred): Document Format Codes.
... context Σ 0..1 BackboneElement Clinical context of document
.... id 0..1 string Unique id for inter-element referencing
.... extension 0..* Extension Additional content defined by implementations
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... encounter 0..* Reference(Encounter | EpisodeOfCare) Context of the document content
.... event 0..* CodeableConcept Main clinical acts documented
Binding: v3 Code System ActCode (example): This list of codes represents the main clinical acts being documented.
.... period Σ 0..1 Period Time of service that is being documented
.... facilityType 0..1 CodeableConcept Kind of facility where patient was seen
Binding: FacilityTypeCodeValueSet (example): XDS Facility Type.
.... practiceSetting 0..1 CodeableConcept Additional details about where the content was created (e.g. clinical specialty)
Binding: PracticeSettingCodeValueSet (example): Additional details about where the content was created (e.g. clinical specialty).
.... sourcePatientInfo 0..1 Reference(Patient) Patient demographics from source
.... related S 0..* Reference(Resource) The governing transaction resource this content supports

doco Documentation for this format

Terminology Bindings

Path Status Usage ValueSet Version Source
DocumentReference.language Base preferred Common Languages 📍4.0.1 FHIR Std.
DocumentReference.status Base required DocumentReferenceStatus 📍4.0.1 FHIR Std.
DocumentReference.docStatus Base required CompositionStatus 📍4.0.1 FHIR Std.
DocumentReference.type Base preferred Document Type Value Set 📍4.0.1 FHIR Std.
DocumentReference.category Base example Document Class Value Set 📍4.0.1 FHIR Std.
DocumentReference.relatesTo.​code Base required DocumentRelationshipType 📍4.0.1 FHIR Std.
DocumentReference.securityLabel Base extensible SecurityLabels 📍4.0.1 FHIR Std.
DocumentReference.content.​attachment.contentType Base required MimeType 📍4.0.1 FHIR Std.
DocumentReference.content.​attachment.language Base preferred Common Languages 📍4.0.1 FHIR Std.
DocumentReference.content.​format Base preferred DocumentReference Format Code Set 📍4.0.1 FHIR Std.
DocumentReference.context.​event Base example v3 Code System ActCode 📦3.0.0 THO v7.3
DocumentReference.context.​facilityType Base example Facility Type Code Value Set 📍4.0.1 FHIR Std.
DocumentReference.context.​practiceSetting Base example Practice Setting Code Value Set 📍4.0.1 FHIR Std.

Constraints

Id Grade Path(s) Description Expression
arex-ent-1 error DocumentReference Content SHALL be referenced by an absolute URL, never embedded. content.attachment.url.exists() and content.attachment.url.startsWith('http')

This structure is derived from DocumentReference

Summary

Mandatory: 8 elements
Must-Support: 13 elements
Fixed: 1 element
Prohibited: 2 elements

Extensions

This structure refers to these extensions:

Key Elements View

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. DocumentReference C 0..* DocumentReference A reference to a document
Constraints: arex-ent-1
... implicitRules ?!Σ 0..1 uri A set of rules under which this content was created
... modifierExtension ?! 0..* Extension Extensions that cannot be ignored
... masterIdentifier SΣ 0..1 Identifier Master Version Specific Identifier
... status ?!Σ 1..1 code current | superseded | entered-in-error
Binding: DocumentReferenceStatus (required): The status of the document reference.
Fixed Value: current
... type SΣ 1..1 CodeableConcept Document type; LOINC document or attachment code where one applies
Binding: DocumentTypeValueSet (preferred): Precise type of clinical document.
... subject SΣ 1..1 Reference(Patient) Who/what is the subject of the document
... date SΣ 1..1 instant When this document reference was created
... content SΣ 1..1 BackboneElement Exactly one content object per entry
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... attachment Σ 1..1 Attachment Where to access the document
..... Slices for extension 1..* Extension Extension
Slice: Unordered, Open by value:url
...... extension:digest S 1..1 (Complex) ARex Digest
URL: https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest
..... contentType SΣ 1..1 code Mime type of the content, with charset etc.
Binding: Mime Types (required): The mime type of an attachment. Any valid mime type is allowed.
Example General: text/plain; charset=UTF-8, image/png
..... url SΣ 1..1 url Uri where the data can be found
Example General: http://www.acme.com/logo-small.png
..... size SΣ 1..1 unsignedInt Octet count as served, declared before retrieval
..... title SΣ 0..1 string Label to display in place of the data
Example General: Official Corporate Logo
.... format SΣ 0..1 Coding Format/content rules for the document
Binding: DocumentReferenceFormatCodeSet (preferred): Document Format Codes.
... context Σ 0..1 BackboneElement Clinical context of document
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... related S 0..* Reference(Resource) The governing transaction resource this content supports

doco Documentation for this format

Terminology Bindings

Path Status Usage ValueSet Version Source
DocumentReference.status Base required DocumentReferenceStatus 📍4.0.1 FHIR Std.
DocumentReference.type Base preferred Document Type Value Set 📍4.0.1 FHIR Std.
DocumentReference.content.​attachment.contentType Base required MimeType 📍4.0.1 FHIR Std.
DocumentReference.content.​format Base preferred DocumentReference Format Code Set 📍4.0.1 FHIR Std.

Constraints

Id Grade Path(s) Description Expression
arex-ent-1 error DocumentReference Content SHALL be referenced by an absolute URL, never embedded. content.attachment.url.exists() and content.attachment.url.startsWith('http')

Differential View

This structure is derived from DocumentReference

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. DocumentReference C 0..* DocumentReference A reference to a document
Constraints: arex-ent-1
... masterIdentifier S 0..1 Identifier Master Version Specific Identifier
... identifier S 0..* Identifier Other identifiers for the document
... status 1..1 code current | superseded | entered-in-error
Fixed Value: current
... subject S 1..1 Reference(Patient) Who/what is the subject of the document
... date S 1..1 instant When this document reference was created
... content S 1..1 BackboneElement Exactly one content object per entry
.... attachment
..... extension 1..* Extension Extension
..... Slices for extension Content/Rules for all slices
...... extension:digest S 1..1 (Complex) ARex Digest
URL: https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest
..... contentType S 1..1 code Mime type of the content, with charset etc.
..... data 0..0 Prohibited. ARex exists to keep content out of the transaction payload.
..... url S 1..1 url Uri where the data can be found
..... size S 1..1 unsignedInt Octet count as served, declared before retrieval
..... hash 0..0 Prohibited. Attachment.hash is SHA-1 in R4; use the ARex Digest extension.
..... title S 0..1 string Label to display in place of the data
.... format S 0..1 Coding Format/content rules for the document
... context
.... related S 0..* Reference(Resource) The governing transaction resource this content supports

doco Documentation for this format

Constraints

Id Grade Path(s) Description Expression
arex-ent-1 error DocumentReference Content SHALL be referenced by an absolute URL, never embedded. content.attachment.url.exists() and content.attachment.url.startsWith('http')

Snapshot View

NameFlagsCard.TypeDescription & Constraints    Filter: Filtersdoco
.. DocumentReference C 0..* DocumentReference A reference to a document
Constraints: arex-ent-1
... id Σ 0..1 id Logical id of this artifact
... meta Σ 0..1 Meta Metadata about the resource
... implicitRules ?!Σ 0..1 uri A set of rules under which this content was created
... text 0..1 Narrative Text summary of the resource, for human interpretation
This profile does not constrain the narrative in regard to content, language, or traceability to data elements
... contained 0..* Resource Contained, inline Resources
... extension 0..* Extension Additional content defined by implementations
... modifierExtension ?! 0..* Extension Extensions that cannot be ignored
... masterIdentifier SΣ 0..1 Identifier Master Version Specific Identifier
... identifier SΣ 0..* Identifier Other identifiers for the document
... status ?!Σ 1..1 code current | superseded | entered-in-error
Binding: DocumentReferenceStatus (required): The status of the document reference.
Fixed Value: current
... docStatus Σ 0..1 code preliminary | final | amended | entered-in-error
Binding: CompositionStatus (required): Status of the underlying document.
... type SΣ 1..1 CodeableConcept Document type; LOINC document or attachment code where one applies
Binding: DocumentTypeValueSet (preferred): Precise type of clinical document.
... category Σ 0..* CodeableConcept Categorization of document
Binding: DocumentClassValueSet (example): High-level kind of a clinical document at a macro level.
... subject SΣ 1..1 Reference(Patient) Who/what is the subject of the document
... date SΣ 1..1 instant When this document reference was created
... author Σ 0..* Reference(Practitioner | PractitionerRole | Organization | Device | Patient | RelatedPerson) Who and/or what authored the document
... authenticator 0..1 Reference(Practitioner | PractitionerRole | Organization) Who/what authenticated the document
... custodian 0..1 Reference(Organization) Organization which maintains the document
... relatesTo Σ 0..* BackboneElement Relationships to other documents
.... id 0..1 string Unique id for inter-element referencing
.... extension 0..* Extension Additional content defined by implementations
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... code Σ 1..1 code replaces | transforms | signs | appends
Binding: DocumentRelationshipType (required): The type of relationship between documents.
.... target Σ 1..1 Reference(DocumentReference) Target of the relationship
... description Σ 0..1 string Human-readable description
... securityLabel Σ 0..* CodeableConcept Document security-tags
Binding: All Security Labels (extensible): Security Labels from the Healthcare Privacy and Security Classification System.
... content SΣ 1..1 BackboneElement Exactly one content object per entry
.... id 0..1 string Unique id for inter-element referencing
.... extension 0..* Extension Additional content defined by implementations
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... attachment Σ 1..1 Attachment Where to access the document
..... id 0..1 string Unique id for inter-element referencing
..... Slices for extension 1..* Extension Extension
Slice: Unordered, Open by value:url
...... extension:digest S 1..1 (Complex) ARex Digest
URL: https://fhir.onyxhealth.io/us/arex/StructureDefinition/arex-digest
..... contentType SΣ 1..1 code Mime type of the content, with charset etc.
Binding: Mime Types (required): The mime type of an attachment. Any valid mime type is allowed.
Example General: text/plain; charset=UTF-8, image/png
..... language Σ 0..1 code Human language of the content (BCP-47)
Binding: CommonLanguages (preferred): A human language.
Additional BindingsPurpose
AllLanguages Max Binding

Example General: en-AU
..... url SΣ 1..1 url Uri where the data can be found
Example General: http://www.acme.com/logo-small.png
..... size SΣ 1..1 unsignedInt Octet count as served, declared before retrieval
..... title SΣ 0..1 string Label to display in place of the data
Example General: Official Corporate Logo
..... creation Σ 0..1 dateTime Date attachment was first created
.... format SΣ 0..1 Coding Format/content rules for the document
Binding: DocumentReferenceFormatCodeSet (preferred): Document Format Codes.
... context Σ 0..1 BackboneElement Clinical context of document
.... id 0..1 string Unique id for inter-element referencing
.... extension 0..* Extension Additional content defined by implementations
.... modifierExtension ?!Σ 0..* Extension Extensions that cannot be ignored even if unrecognized
.... encounter 0..* Reference(Encounter | EpisodeOfCare) Context of the document content
.... event 0..* CodeableConcept Main clinical acts documented
Binding: v3 Code System ActCode (example): This list of codes represents the main clinical acts being documented.
.... period Σ 0..1 Period Time of service that is being documented
.... facilityType 0..1 CodeableConcept Kind of facility where patient was seen
Binding: FacilityTypeCodeValueSet (example): XDS Facility Type.
.... practiceSetting 0..1 CodeableConcept Additional details about where the content was created (e.g. clinical specialty)
Binding: PracticeSettingCodeValueSet (example): Additional details about where the content was created (e.g. clinical specialty).
.... sourcePatientInfo 0..1 Reference(Patient) Patient demographics from source
.... related S 0..* Reference(Resource) The governing transaction resource this content supports

doco Documentation for this format

Terminology Bindings

Path Status Usage ValueSet Version Source
DocumentReference.language Base preferred Common Languages 📍4.0.1 FHIR Std.
DocumentReference.status Base required DocumentReferenceStatus 📍4.0.1 FHIR Std.
DocumentReference.docStatus Base required CompositionStatus 📍4.0.1 FHIR Std.
DocumentReference.type Base preferred Document Type Value Set 📍4.0.1 FHIR Std.
DocumentReference.category Base example Document Class Value Set 📍4.0.1 FHIR Std.
DocumentReference.relatesTo.​code Base required DocumentRelationshipType 📍4.0.1 FHIR Std.
DocumentReference.securityLabel Base extensible SecurityLabels 📍4.0.1 FHIR Std.
DocumentReference.content.​attachment.contentType Base required MimeType 📍4.0.1 FHIR Std.
DocumentReference.content.​attachment.language Base preferred Common Languages 📍4.0.1 FHIR Std.
DocumentReference.content.​format Base preferred DocumentReference Format Code Set 📍4.0.1 FHIR Std.
DocumentReference.context.​event Base example v3 Code System ActCode 📦3.0.0 THO v7.3
DocumentReference.context.​facilityType Base example Facility Type Code Value Set 📍4.0.1 FHIR Std.
DocumentReference.context.​practiceSetting Base example Practice Setting Code Value Set 📍4.0.1 FHIR Std.

Constraints

Id Grade Path(s) Description Expression
arex-ent-1 error DocumentReference Content SHALL be referenced by an absolute URL, never embedded. content.attachment.url.exists() and content.attachment.url.startsWith('http')

This structure is derived from DocumentReference

Summary

Mandatory: 8 elements
Must-Support: 13 elements
Fixed: 1 element
Prohibited: 2 elements

Extensions

This structure refers to these extensions:

 

Other representations of profile: CSV, Excel, Schematron