FHIR IG analytics| Package | hl7.fhir.uv.extensions |
| Resource Type | StructureDefinition |
| Id | StructureDefinition-codesystem-reservedCodeSpace.json |
| FHIR Version | R5 |
| Source | https://build.fhir.org/ig/HL7/fhir-extensions/StructureDefinition-codesystem-reservedCodeSpace.html |
| URL | http://hl7.org/fhir/StructureDefinition/codesystem-reservedCodeSpace |
| Version | 5.3.0 |
| Status | draft |
| Date | 2026-10-03 |
| Name | ReservedCodeSpace |
| Title | Reserved Code Space |
| Realm | uv |
| Authority | hl7 |
| Description | This extension is used to describe a set of concept codes that has been allocated by the code system steward for users to create their own codes. |
| Purpose | Some code systems reserve part of their code space for private codes that anyone can create and use. Without a way to describe this, validators report such codes as invalid. Validators that check codes against a code system with a reserved code space do not flag codes in that space as invalid because of the code system definition (though they might because of value set considerations), nor do they validate the display or provide definitions for such codes. |
| Type | Extension |
| Kind | complex-type |
No resources found
No resources found
No extension usage examples found
Note: links and images are rebased to the (stated) source
Generated Narrative: StructureDefinition codesystem-reservedCodeSpace
| Name | Flags | Card. | Type | Description & Constraints |
|---|---|---|---|---|
  Extension | 0..* | Extension | Set of codes reserved for users to create their own codes | |
  extension | 1..* | Extension | Extension | |
 Slices for extension | Content/Rules for all slices | |||
   extension:reservedCodeSpace | 1..1 | Extension | Regular expression for the reserved codes | |
  extension | 0..0 | Extension | ||
| url | 1..1 | uri | "reservedCodeSpace" | |
  value[x] | 1..1 | string | Value of extension | |
 extension:description | 0..1 | Extension | Narrative explaining the set of codes | |
 extension | 0..0 | Extension | ||
| url | 1..1 | uri | "description" | |
| value[x] | 1..1 | markdown | Value of extension | |
| url | 1..1 | uri | "http://hl7.org/fhir/StructureDefinition/codesystem-reservedCodeSpace" | |
 value[x] | 0..0 | Value of extension | ||
| Documentation for this format | ||||
FHIR
FHIRsmith{
"resourceType": "StructureDefinition",
"id": "codesystem-reservedCodeSpace",
"text": {
"status": "extensions",
"div": "<!-- snip (see above) -->"
},
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
"valueCode": "fhir"
},
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
"valueInteger": 0
},
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
"valueCode": "draft"
},
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-type-characteristics",
"valueCode": "can-bind"
}
],
"url": "http://hl7.org/fhir/StructureDefinition/codesystem-reservedCodeSpace",
"identifier": [
{
"system": "urn:ietf:rfc:3986",
"value": "urn:oid:2.16.840.1.113883.4.642.40.97.42.152"
}
],
"version": "5.3.0",
"name": "ReservedCodeSpace",
"title": "Reserved Code Space",
"status": "draft",
"experimental": false,
"date": "2026-10-03",
"publisher": "HL7 International / FHIR Infrastructure",
"contact": [
{
"telecom": [
{
"system": "url",
"value": "http://www.hl7.org/Special/committees/fiwg"
}
]
}
],
"description": "This extension is used to describe a set of concept codes that has been allocated by the code system steward for users to create their own codes.",
"jurisdiction": [
{
"coding": [
{
"system": "http://unstats.un.org/unsd/methods/m49/m49.htm",
"code": "001"
}
]
}
],
"purpose": "Some code systems reserve part of their code space for private codes that anyone can create and use. Without a way to describe this, validators report such codes as invalid. Validators that check codes against a code system with a reserved code space do not flag codes in that space as invalid because of the code system definition (though they might because of value set considerations), nor do they validate the display or provide definitions for such codes.",
"fhirVersion": "5.0.0",
"mapping": [
{
"identity": "rim",
"uri": "http://hl7.org/v3",
"name": "RIM Mapping"
}
],
"kind": "complex-type",
"abstract": false,
"context": [
{
"type": "element",
"expression": "CodeSystem"
}
],
"type": "Extension",
"baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension",
"derivation": "constraint",
"snapshot": {
"extension": [
{
"url": "http://hl7.org/fhir/tools/StructureDefinition/snapshot-base-version",
"valueString": "5.0.0"
}
],
"element": [
{
"id": "Extension",
"path": "Extension",
"short": "Set of codes reserved for users to create their own codes",
"definition": "This extension is used to describe a set of concept codes that has been allocated by the code system steward for users to create their own codes.",
"comment": "A code system might have more than one reserved code space, if there are different kinds of reserved private space.",
"min": 0,
"max": "*",
"base": {
"path": "Extension",
"min": 0,
"max": "*"
},
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
},
{
"key": "ext-1",
"severity": "error",
"human": "Must have either extensions or value[x], not both",
"expression": "extension.exists() != value.exists()",
"source": "http://hl7.org/fhir/StructureDefinition/Extension"
}
],
"isModifier": false
},
{
"id": "Extension.id",
"path": "Extension.id",
"representation": [
"xmlAttr"
],
"short": "Unique id for inter-element referencing",
"definition": "Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.",
"min": 0,
"max": "1",
"base": {
"path": "Element.id",
"min": 0,
"max": "1"
},
"type": [
{
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
"valueUrl": "id"
}
],
"code": "http://hl7.org/fhirpath/System.String"
}
],
"condition": [
"ele-1"
],
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "n/a"
}
]
},
{
"id": "Extension.extension",
"path": "Extension.extension",
"slicing": {
"discriminator": [
{
"type": "value",
"path": "url"
}
],
"description": "Extensions are always sliced by (at least) url",
"rules": "open"
},
"short": "Extension",
"definition": "An Extension",
"min": 1,
"max": "*",
"base": {
"path": "Element.extension",
"min": 0,
"max": "*"
},
"type": [
{
"code": "Extension"
}
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
},
{
"key": "ext-1",
"severity": "error",
"human": "Must have either extensions or value[x], not both",
"expression": "extension.exists() != value.exists()",
"source": "http://hl7.org/fhir/StructureDefinition/Extension"
}
],
"isModifier": false,
"isSummary": false
},
{
"id": "Extension.extension:reservedCodeSpace",
"path": "Extension.extension",
"sliceName": "reservedCodeSpace",
"short": "Regular expression for the reserved codes",
"definition": "Regular expression to identify the set of concept codes allocated for users of the code system to create their own codes. This value must be a regular expression.",
"comment": "The regular expression is matched against the whole code.",
"min": 1,
"max": "1",
"base": {
"path": "Element.extension",
"min": 0,
"max": "*"
},
"type": [
{
"code": "Extension"
}
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
},
{
"key": "ext-1",
"severity": "error",
"human": "Must have either extensions or value[x], not both",
"expression": "extension.exists() != value.exists()",
"source": "http://hl7.org/fhir/StructureDefinition/Extension"
}
],
"isModifier": false,
"isSummary": false
},
{
"id": "Extension.extension:reservedCodeSpace.id",
"path": "Extension.extension.id",
"representation": [
"xmlAttr"
],
"short": "Unique id for inter-element referencing",
"definition": "Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.",
"min": 0,
"max": "1",
"base": {
"path": "Element.id",
"min": 0,
"max": "1"
},
"type": [
{
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
"valueUrl": "id"
}
],
"code": "http://hl7.org/fhirpath/System.String"
}
],
"condition": [
"ele-1"
],
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "n/a"
}
]
},
{
"id": "Extension.extension:reservedCodeSpace.extension",
"path": "Extension.extension.extension",
"slicing": {
"discriminator": [
{
"type": "value",
"path": "url"
}
],
"description": "Extensions are always sliced by (at least) url",
"rules": "open"
},
"short": "Extension",
"definition": "An Extension",
"min": 0,
"max": "0",
"base": {
"path": "Element.extension",
"min": 0,
"max": "*"
},
"type": [
{
"code": "Extension"
}
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
},
{
"key": "ext-1",
"severity": "error",
"human": "Must have either extensions or value[x], not both",
"expression": "extension.exists() != value.exists()",
"source": "http://hl7.org/fhir/StructureDefinition/Extension"
}
],
"isModifier": false,
"isSummary": false
},
{
"id": "Extension.extension:reservedCodeSpace.url",
"path": "Extension.extension.url",
"representation": [
"xmlAttr"
],
"short": "identifies the meaning of the extension",
"definition": "Source of the definition for the extension code - a logical name or a URL.",
"comment": "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.",
"min": 1,
"max": "1",
"base": {
"path": "Extension.url",
"min": 1,
"max": "1"
},
"type": [
{
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
"valueUrl": "uri"
}
],
"code": "http://hl7.org/fhirpath/System.String"
}
],
"fixedUri": "reservedCodeSpace",
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "N/A"
}
]
},
{
"id": "Extension.extension:reservedCodeSpace.value[x]",
"path": "Extension.extension.value[x]",
"short": "Value of extension",
"definition": "Value of extension - must be one of a constrained set of the data types (see [Extensibility](http://hl7.org/fhir/R5/extensibility.html) for a list).",
"min": 1,
"max": "1",
"base": {
"path": "Extension.value[x]",
"min": 0,
"max": "1"
},
"type": [
{
"code": "string"
}
],
"condition": [
"ext-1"
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
}
],
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "N/A"
}
]
},
{
"id": "Extension.extension:description",
"path": "Extension.extension",
"sliceName": "description",
"short": "Narrative explaining the set of codes",
"definition": "Narrative explaining the set of concept codes.",
"min": 0,
"max": "1",
"base": {
"path": "Element.extension",
"min": 0,
"max": "*"
},
"type": [
{
"code": "Extension"
}
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
},
{
"key": "ext-1",
"severity": "error",
"human": "Must have either extensions or value[x], not both",
"expression": "extension.exists() != value.exists()",
"source": "http://hl7.org/fhir/StructureDefinition/Extension"
}
],
"isModifier": false,
"isSummary": false
},
{
"id": "Extension.extension:description.id",
"path": "Extension.extension.id",
"representation": [
"xmlAttr"
],
"short": "Unique id for inter-element referencing",
"definition": "Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.",
"min": 0,
"max": "1",
"base": {
"path": "Element.id",
"min": 0,
"max": "1"
},
"type": [
{
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
"valueUrl": "id"
}
],
"code": "http://hl7.org/fhirpath/System.String"
}
],
"condition": [
"ele-1"
],
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "n/a"
}
]
},
{
"id": "Extension.extension:description.extension",
"path": "Extension.extension.extension",
"slicing": {
"discriminator": [
{
"type": "value",
"path": "url"
}
],
"description": "Extensions are always sliced by (at least) url",
"rules": "open"
},
"short": "Extension",
"definition": "An Extension",
"min": 0,
"max": "0",
"base": {
"path": "Element.extension",
"min": 0,
"max": "*"
},
"type": [
{
"code": "Extension"
}
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
},
{
"key": "ext-1",
"severity": "error",
"human": "Must have either extensions or value[x], not both",
"expression": "extension.exists() != value.exists()",
"source": "http://hl7.org/fhir/StructureDefinition/Extension"
}
],
"isModifier": false,
"isSummary": false
},
{
"id": "Extension.extension:description.url",
"path": "Extension.extension.url",
"representation": [
"xmlAttr"
],
"short": "identifies the meaning of the extension",
"definition": "Source of the definition for the extension code - a logical name or a URL.",
"comment": "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.",
"min": 1,
"max": "1",
"base": {
"path": "Extension.url",
"min": 1,
"max": "1"
},
"type": [
{
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
"valueUrl": "uri"
}
],
"code": "http://hl7.org/fhirpath/System.String"
}
],
"fixedUri": "description",
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "N/A"
}
]
},
{
"id": "Extension.extension:description.value[x]",
"path": "Extension.extension.value[x]",
"short": "Value of extension",
"definition": "Value of extension - must be one of a constrained set of the data types (see [Extensibility](http://hl7.org/fhir/R5/extensibility.html) for a list).",
"min": 1,
"max": "1",
"base": {
"path": "Extension.value[x]",
"min": 0,
"max": "1"
},
"type": [
{
"code": "markdown"
}
],
"condition": [
"ext-1"
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
}
],
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "N/A"
}
]
},
{
"id": "Extension.url",
"path": "Extension.url",
"representation": [
"xmlAttr"
],
"short": "identifies the meaning of the extension",
"definition": "Source of the definition for the extension code - a logical name or a URL.",
"comment": "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.",
"min": 1,
"max": "1",
"base": {
"path": "Extension.url",
"min": 1,
"max": "1"
},
"type": [
{
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
"valueUrl": "uri"
}
],
"code": "http://hl7.org/fhirpath/System.String"
}
],
"fixedUri": "http://hl7.org/fhir/StructureDefinition/codesystem-reservedCodeSpace",
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "N/A"
}
]
},
{
"id": "Extension.value[x]",
"path": "Extension.value[x]",
"short": "Value of extension",
"definition": "Value of extension - must be one of a constrained set of the data types (see [Extensibility](http://hl7.org/fhir/R5/extensibility.html) for a list).",
"min": 0,
"max": "0",
"base": {
"path": "Extension.value[x]",
"min": 0,
"max": "1"
},
"type": [
{
"code": "base64Binary"
},
{
"code": "boolean"
},
{
"code": "canonical"
},
{
"code": "code"
},
{
"code": "date"
},
{
"code": "dateTime"
},
{
"code": "decimal"
},
{
"code": "id"
},
{
"code": "instant"
},
{
"code": "integer"
},
{
"code": "integer64"
},
{
"code": "markdown"
},
{
"code": "oid"
},
{
"code": "positiveInt"
},
{
"code": "string"
},
{
"code": "time"
},
{
"code": "unsignedInt"
},
{
"code": "uri"
},
{
"code": "url"
},
{
"code": "uuid"
},
{
"code": "Address"
},
{
"code": "Age"
},
{
"code": "Annotation"
},
{
"code": "Attachment"
},
{
"code": "CodeableConcept"
},
{
"code": "CodeableReference"
},
{
"code": "Coding"
},
{
"code": "ContactPoint"
},
{
"code": "Count"
},
{
"code": "Distance"
},
{
"code": "Duration"
},
{
"code": "HumanName"
},
{
"code": "Identifier"
},
{
"code": "Money"
},
{
"code": "Period"
},
{
"code": "Quantity"
},
{
"code": "Range"
},
{
"code": "Ratio"
},
{
"code": "RatioRange"
},
{
"code": "Reference"
},
{
"code": "SampledData"
},
{
"code": "Signature"
},
{
"code": "Timing"
},
{
"code": "ContactDetail"
},
{
"code": "DataRequirement"
},
{
"code": "Expression"
},
{
"code": "ParameterDefinition"
},
{
"code": "RelatedArtifact"
},
{
"code": "TriggerDefinition"
},
{
"code": "UsageContext"
},
{
"code": "Availability"
},
{
"code": "ExtendedContactDetail"
},
{
"code": "Dosage"
},
{
"code": "Meta"
}
],
"condition": [
"ext-1"
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() or (children().count() > id.count())",
"source": "http://hl7.org/fhir/StructureDefinition/Element"
}
],
"isModifier": false,
"isSummary": false,
"mapping": [
{
"identity": "rim",
"map": "N/A"
}
]
}
]
},
"differential": {
"element": [
{
"id": "Extension",
"path": "Extension",
"short": "Set of codes reserved for users to create their own codes",
"definition": "This extension is used to describe a set of concept codes that has been allocated by the code system steward for users to create their own codes.",
"comment": "A code system might have more than one reserved code space, if there are different kinds of reserved private space.",
"min": 0,
"max": "*"
},
{
"id": "Extension.extension",
"path": "Extension.extension",
"min": 1
},
{
"id": "Extension.extension:reservedCodeSpace",
"path": "Extension.extension",
"sliceName": "reservedCodeSpace",
"short": "Regular expression for the reserved codes",
"definition": "Regular expression to identify the set of concept codes allocated for users of the code system to create their own codes. This value must be a regular expression.",
"comment": "The regular expression is matched against the whole code.",
"min": 1,
"max": "1"
},
{
"id": "Extension.extension:reservedCodeSpace.extension",
"path": "Extension.extension.extension",
"max": "0"
},
{
"id": "Extension.extension:reservedCodeSpace.url",
"path": "Extension.extension.url",
"fixedUri": "reservedCodeSpace"
},
{
"id": "Extension.extension:reservedCodeSpace.value[x]",
"path": "Extension.extension.value[x]",
"min": 1,
"type": [
{
"code": "string"
}
]
},
{
"id": "Extension.extension:description",
"path": "Extension.extension",
"sliceName": "description",
"short": "Narrative explaining the set of codes",
"definition": "Narrative explaining the set of concept codes.",
"min": 0,
"max": "1"
},
{
"id": "Extension.extension:description.extension",
"path": "Extension.extension.extension",
"max": "0"
},
{
"id": "Extension.extension:description.url",
"path": "Extension.extension.url",
"fixedUri": "description"
},
{
"id": "Extension.extension:description.value[x]",
"path": "Extension.extension.value[x]",
"min": 1,
"type": [
{
"code": "markdown"
}
]
},
{
"id": "Extension.url",
"path": "Extension.url",
"fixedUri": "http://hl7.org/fhir/StructureDefinition/codesystem-reservedCodeSpace"
},
{
"id": "Extension.value[x]",
"path": "Extension.value[x]",
"max": "0"
}
]
}
}