Netherlands - Generic Functions for data exchange Implementation Guide
0.2.0-ballot - ci-build

Netherlands - Generic Functions for data exchange Implementation Guide, published by Ministerie van Volksgezondheid, Welzijn en Sport. This guide is not an authorized publication; it is the continuous build for version 0.2.0-ballot built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/minvws/generiekefuncties-docs/ and changes regularly. See the Directory of published versions

## Extension: NlGfDeviceIdentifier - Detailed Descriptions

Draft as of 2026-03-24

Definitions for the nl-gf-device-identifier 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 | An identifier for a device, such as a software application. Optional Extension Element - found in all resources.
Short | NL Generic Functions Device IdentifierOptional Extensions Element
Control | 0..* This element is affected by the following invariants: ele-1
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()`) 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 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.
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 | `http://minvws.github.io/generiekefuncties-docs/StructureDefinition/nl-gf-device-identifier`
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 | 0..1
Type | Reference(NL Generic Functions Device Profile), date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, Coding, SampledData, id, positiveInt, Distance, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, CodeableConcept, ParameterDefinition, dateTime, code, string, Contributor, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Expression, 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()))
8. Extension.value[x].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.
Short | Logical 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).
Note | This is a business identifier, not a resource identifier (see discussion)
Control | 10..1
Type | Identifier
Is Modifier | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
10. Extension.value[x].identifier.use
Definition | The purpose of this identifier.
Short | usual | official | temp | secondary | old (If known)
Comments | Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.
Control | 0..1
Binding | The codes SHALL be taken from IdentifierUse http://hl7.org/fhir/ValueSet/identifier-use|4.0.1 (required to `http://hl7.org/fhir/ValueSet/identifier-use|4.0.1` ) Identifies the purpose for this identifier, if known .
Type | code
Is Modifier | true because This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one.
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
12. Extension.value[x].identifier.system
Definition | Establishes the namespace for the value - that is, a URL that describes a set values that are unique.
Short | The namespace for the identifier value
Comments | Identifier.system is always case sensitive.
Control | 0..1
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.
Pattern Value | `urn:ietf:rfc:3986`
Example | General: http://www.acme.com/identifiers/patient
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
14. Extension.value[x].identifier.value
Definition | The portion of the identifier typically relevant to the user and which is unique within the context of the system.
Short | The value that is unique
Comments | If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.
Control | 10..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Example | General: 123456
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count())) device-identifier-urn: The device identifier must be a URN with a valid UUID or OID. (`startsWith('urn:uuid:') or startsWith('urn:oid:')`)

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

0. Extension
Definition | An identifier for a device, such as a software application.
Short | NL Generic Functions Device Identifier
2. Extension.extension
Control | 0..0
4. Extension.url
Fixed Value | `http://minvws.github.io/generiekefuncties-docs/StructureDefinition/nl-gf-device-identifier`
6. Extension.value[x]
Type | Reference(NL Generic Functions Device Profile), date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, Coding, SampledData, id, positiveInt, Distance, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, CodeableConcept, ParameterDefinition, dateTime, code, string, Contributor, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Expression, Signature, unsignedInt, time
[x] Note | SeeChoice of Data Typesfor further information about how to use [x]
8. Extension.value[x].identifier
Note | This is a business identifier, not a resource identifier (see discussion)
Control | 1..?
10. Extension.value[x].identifier.system
Pattern Value | `urn:ietf:rfc:3986`
12. Extension.value[x].identifier.value
Control | 1..?
Invariants | device-identifier-urn: The device identifier must be a URN with a valid UUID or OID. (`startsWith('urn:uuid:') or startsWith('urn:oid:')`)

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

0. Extension
Definition | An identifier for a device, such as a software application.
Short | NL Generic Functions Device Identifier
Control | 0..* This element is affected by the following invariants: ele-1
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
Type | string
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 | `http://minvws.github.io/generiekefuncties-docs/StructureDefinition/nl-gf-device-identifier`
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 | 0..1
Type | Reference(NL Generic Functions Device Profile)
[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())`)
10. Extension.value[x].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
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
12. Extension.value[x].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.
Short | Additional 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..*
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.value[x].extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
14. Extension.value[x].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.
Short | Literal 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.
Control | 0..1 This element is affected by the following invariants: ref-1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
16. Extension.value[x].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).
Short | Type 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.
Control | 0..1
Binding | Unless not suitable, these codes SHALL be taken from ResourceType (extensible to `http://hl7.org/fhir/ValueSet/resource-types|4.0.1` ) Aa resource (or, for logical models, the URI of the logical model).
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
18. Extension.value[x].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.
Short | Logical 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).
Note | This is a business identifier, not a resource identifier (see discussion)
Control | 1..1
Type | Identifier
Is Modifier | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
20. Extension.value[x].identifier.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
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
22. Extension.value[x].identifier.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.
Short | Additional 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..*
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.value[x].identifier.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
24. Extension.value[x].identifier.use
Definition | The purpose of this identifier.
Short | usual | official | temp | secondary | old (If known)
Comments | Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.
Control | 0..1
Binding | The codes SHALL be taken from IdentifierUse (required to `http://hl7.org/fhir/ValueSet/identifier-use|4.0.1` ) Identifies the purpose for this identifier, if known .
Type | code
Is Modifier | true because This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one.
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
26. Extension.value[x].identifier.type
Definition | A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.
Short | Description of identifier
Comments | This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.
Control | 0..1
Binding | Unless not suitable, these codes SHALL be taken from Identifier Type Codes (extensible to `http://hl7.org/fhir/ValueSet/identifier-type|4.0.1` ) A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.
Type | CodeableConcept
Is Modifier | false
Summary | true
Requirements | Allows users to make use of identifiers when the identifier system is not known.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
28. Extension.value[x].identifier.system
Definition | Establishes the namespace for the value - that is, a URL that describes a set values that are unique.
Short | The namespace for the identifier value
Comments | Identifier.system is always case sensitive.
Control | 0..1
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.
Pattern Value | `urn:ietf:rfc:3986`
Example | General: http://www.acme.com/identifiers/patient
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
30. Extension.value[x].identifier.value
Definition | The portion of the identifier typically relevant to the user and which is unique within the context of the system.
Short | The value that is unique
Comments | If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.
Control | 1..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Example | General: 123456
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) device-identifier-urn: The device identifier must be a URN with a valid UUID or OID. (`startsWith('urn:uuid:') or startsWith('urn:oid:')`)
32. Extension.value[x].identifier.period
Definition | Time period during which identifier is/was valid for use.
Short | Time period when id is/was valid for use
Control | 0..1
Type | Period
Is Modifier | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
34. Extension.value[x].identifier.assigner
Definition | Organization that issued/manages the identifier.
Short | Organization that issued id (may be just text)
Comments | The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.
Control | 0..1
Type | Reference(Organization)
Is Modifier | false
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
36. Extension.value[x].display
Definition | Plain text narrative that identifies the resource in addition to the resource reference.
Short | Text 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.
Control | 0..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)