Mobile access to Health Documents (MHD)
5.0.1-current - ci-build

Mobile access to Health Documents (MHD), published by IHE IT Infrastructure Technical Committee. This guide is not an authorized publication; it is the continuous build for version 5.0.1-current built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/IHE/ITI.MHD/ and changes regularly. See the Directory of published versions

## Extension: ReferenceId - Detailed Descriptions

Active as of 2026-01-13

Definitions for the ihe-referenceId extension.

- Key Elements Table
- Differential Elements Table
- Snapshot Elements Table

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

0. Extension
Definition | This extension holds values from DocumentEntry.referenceIdList that are not appropriate for .context or .basedOn. This extension can hold any identifier that is related to the DocumentReference. This extension is added for FHIR R5 as DocumentReference does not have a .context.related element, and this extension will not be needed in R6 as there is a DocumentReference.related element there. Optional Extension Element - found in all resources.
Short | Holds values from DocumentEntry.referenceIdList that are not appropriate for .context or .basedOnOptional Extensions Element
Control | 0..*
Is Modifier | false
Invariants | ele-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())
2. Extension.extension
Definition | An Extension 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 managable, 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.
Short | ExtensionAdditional 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.
Control | 0..0*
Type | Extension
Is Modifier | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-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())
Slicing | This element introduces a set of slices on `Extension.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
4. Extension.url
Definition | Source of the definition for the extension code - a logical name or a URL.
Short | identifies the meaning of the extension
Comments | The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.
Control | 1..1
Type | uri
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
Fixed Value | `https://profiles.ihe.net/ITI/MHD/StructureDefinition/ihe-referenceId`
6. Extension.value[x]
Definition | Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).
Short | Value of extension
Control | 10..1 This element is affected by the following invariants: ext-1
Type | Identifier, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, RatioRange, Coding, SampledData, id, positiveInt, Distance, Availability, integer64, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, ExtendedContactDetail, CodeableConcept, ParameterDefinition, dateTime, code, string, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Expression, CodeableReference, Signature, unsignedInt, time
[x] Note | SeeChoice of Data Typesfor further information about how to use [x]
Is Modifier | false
Summary | false
Invariants | ele-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. Extension
Definition | This extension holds values from DocumentEntry.referenceIdList that are not appropriate for .context or .basedOn. This extension can hold any identifier that is related to the DocumentReference. This extension is added for FHIR R5 as DocumentReference does not have a .context.related element, and this extension will not be needed in R6 as there is a DocumentReference.related element there.
Short | Holds values from DocumentEntry.referenceIdList that are not appropriate for .context or .basedOn
2. Extension.extension
Control | 0..0
4. Extension.url
Fixed Value | `https://profiles.ihe.net/ITI/MHD/StructureDefinition/ihe-referenceId`
6. Extension.value[x]
Control | 1..?
Type | Identifier, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, RatioRange, Coding, SampledData, id, positiveInt, Distance, Availability, integer64, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, ExtendedContactDetail, CodeableConcept, ParameterDefinition, dateTime, code, string, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Expression, CodeableReference, Signature, unsignedInt, time
[x] Note | SeeChoice of Data Typesfor further information about how to use [x]

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

0. Extension
Definition | This extension holds values from DocumentEntry.referenceIdList that are not appropriate for .context or .basedOn. This extension can hold any identifier that is related to the DocumentReference. This extension is added for FHIR R5 as DocumentReference does not have a .context.related element, and this extension will not be needed in R6 as there is a DocumentReference.related element there.
Short | Holds values from DocumentEntry.referenceIdList that are not appropriate for .context or .basedOn
Control | 0..*
Is Modifier | false
Invariants | ele-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()`)
2. Extension.id
Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.
Short | Unique id for inter-element referencing
Control | 0..1 This element is affected by the following invariants: ele-1
Type | id
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
4. Extension.extension
Definition | An Extension
Short | Extension
Control | 0..0
Type | Extension
Is Modifier | false
Summary | false
Invariants | ele-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()`)
Slicing | This element introduces a set of slices on `Extension.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
6. Extension.url
Definition | Source of the definition for the extension code - a logical name or a URL.
Short | identifies the meaning of the extension
Comments | The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.
Control | 1..1
Type | uri
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
Fixed Value | `https://profiles.ihe.net/ITI/MHD/StructureDefinition/ihe-referenceId`
8. Extension.value[x]
Definition | Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).
Short | Value of extension
Control | 1..1 This element is affected by the following invariants: ext-1
Type | Identifier
[x] Note | SeeChoice of Data Typesfor further information about how to use [x]
Is Modifier | false
Summary | false
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)