FHIR IG analytics
| Package | hl7.fhir.uv.xver-r4.r3 |
| Resource Type | StructureDefinition |
| Id | StructureDefinition-ext-R4-Observation.focus.json |
| FHIR Version | R3 |
| Source | http://hl7.org/fhir/uv/xver-r4.r3/0.1.0/StructureDefinition-ext-R4-Observation.focus.html |
| URL | http://hl7.org/fhir/4.0/StructureDefinition/extension-Observation.focus |
| Version | 0.1.0 |
| Status | active |
| Date | 2026-03-17T21:02:03.8104715+00:00 |
| Name | ExtensionObservation_Focus |
| Title | R4: What the observation is about, when it is not about the subject of record (new) |
| Realm | uv |
| Authority | hl7 |
| Description | R4: `Observation.focus` (new:Reference(Resource)) |
| Purpose | This extension is part of the cross-version definitions generated to enable use of the
element `Observation.focus` as defined in FHIR R4
in FHIR STU3.
The source element is defined as:
`Observation.focus` 0..* `Reference(http://hl7.org/fhir/StructureDefinition/Resource)`
Following are the generation technical comments:
Element `Observation.focus` has a context of Observation.related based on following the parent source element upwards and mapping to `Observation`.
Element `Observation.focus` has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element). |
| Type | Extension |
| Kind | complex-type |
Resources that use this resource
Resources that this resource uses
| StructureDefinition |
| hl7.fhir.uv.xver-r4.r4b#0.1.0 | profile-Resource | Cross-version Profile for R4.Resource for use in FHIR R4B |
Examples of Use for Extension
No extension usage examples found
Narrative
Note: links and images are rebased to the (stated) source
Source1
{
"resourceType": "StructureDefinition",
"id": "ext-R4-Observation.focus",
"text": {
"status": "extensions",
"div": "<!-- snip (see above) -->"
},
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
"valueCode": "fhir"
},
{
"extension": [
{
"url": "packageId",
"valueId": "hl7.fhir.uv.xver-r4.r3"
},
{
"url": "version",
"valueString": "0.1.0"
},
{
"url": "uri",
"valueUri": "http://hl7.org/fhir/uv/xver/ImplementationGuide/hl7.fhir.uv.xver-r4.r3"
}
],
"url": "http://hl7.org/fhir/StructureDefinition/package-source"
},
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
"valueInteger": 0,
"_valueInteger": {
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom",
"valueUri": "http://hl7.org/fhir/uv/xver/ImplementationGuide/hl7.fhir.uv.xver-r4.r3"
}
]
}
},
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
"valueCode": "trial-use",
"_valueCode": {
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom",
"valueUri": "http://hl7.org/fhir/uv/xver/ImplementationGuide/hl7.fhir.uv.xver-r4.r3"
}
]
}
}
],
"url": "http://hl7.org/fhir/4.0/StructureDefinition/extension-Observation.focus",
"version": "0.1.0",
"name": "ExtensionObservation_Focus",
"title": "R4: What the observation is about, when it is not about the subject of record (new)",
"status": "active",
"experimental": false,
"date": "2026-03-17T21:02:03.8104715+00:00",
"publisher": "FHIR Infrastructure",
"contact": [
{
"name": "FHIR Infrastructure",
"telecom": [
{
"system": "url",
"value": "http://www.hl7.org/Special/committees/fiwg"
}
]
}
],
"description": "R4: `Observation.focus` (new:Reference(Resource))",
"jurisdiction": [
{
"coding": [
{
"system": "http://unstats.un.org/unsd/methods/m49/m49.htm",
"code": "001",
"display": "World"
}
]
}
],
"purpose": "This extension is part of the cross-version definitions generated to enable use of the\r\nelement `Observation.focus` as defined in FHIR R4\r\nin FHIR STU3.\r\n\r\nThe source element is defined as:\r\n`Observation.focus` 0..* `Reference(http://hl7.org/fhir/StructureDefinition/Resource)`\r\n\r\nFollowing are the generation technical comments:\r\nElement `Observation.focus` has a context of Observation.related based on following the parent source element upwards and mapping to `Observation`.\nElement `Observation.focus` has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).",
"fhirVersion": "3.0.2",
"mapping": [
{
"identity": "rim",
"uri": "http://hl7.org/v3",
"name": "RIM Mapping"
}
],
"kind": "complex-type",
"abstract": false,
"contextType": "resource",
"context": [
"Observation.related"
],
"type": "Extension",
"baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension",
"derivation": "constraint",
"snapshot": {
"element": [
{
"id": "Extension",
"path": "Extension",
"short": "R4: What the observation is about, when it is not about the subject of record (new)",
"definition": "R4: `Observation.focus` (new:Reference(Resource))",
"comment": "Element `Observation.focus` has a context of Observation.related based on following the parent source element upwards and mapping to `Observation`.\nElement `Observation.focus` has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).\nTypically, an observation is made about the subject - a patient, or group of patients, location, or device - and the distinction between the subject and what is directly measured for an observation is specified in the observation code itself ( e.g., \"Blood Glucose\") and does not need to be represented separately using this element. Use `specimen` if a reference to a specimen is required. If a code is required instead of a resource use either `bodysite` for bodysites or the standard extension [focusCode](https://hl7.org/fhir/extension-observation-focuscode.html).",
"min": 0,
"max": "*",
"base": {
"path": "Extension",
"min": 0,
"max": "*"
},
"condition": [
"ele-1"
],
"constraint": [
{
"key": "ele-1",
"severity": "error",
"human": "All FHIR elements must have a @value or children",
"expression": "hasValue() | (children().count() > id.count())",
"xpath": "@value|f:*|h:div",
"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()",
"xpath": "exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')])",
"source": "http://hl7.org/fhir/StructureDefinition/Extension"
}
],
"isModifier": false
},
{
"id": "Extension.id",
"path": "Extension.id",
"representation": [
"xmlAttr"
],
"short": "xml:id (or equivalent in JSON)",
"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": [
{
"code": "string"
}
],
"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": "Additional Content defined by implementations",
"definition": "May be used to represent additional information that is not part of the basic definition of the element. In order 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.",
"comment": "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.",
"alias": [
"extensions",
"user content"
],
"min": 0,
"max": "*",
"base": {
"path": "Element.extension",
"min": 0,
"max": "*"
},
"type": [
{
"code": "Extension"
}
],
"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": [
{
"code": "uri"
}
],
"fixedUri": "http://hl7.org/fhir/4.0/StructureDefinition/extension-Observation.focus",
"mapping": [
{
"identity": "rim",
"map": "N/A"
}
]
},
{
"id": "Extension.value[x]",
"path": "Extension.value[x]",
"short": "What the observation is about, when it is not about the subject of record",
"definition": "The actual focus of an observation when it is not the patient of record representing something or someone associated with the patient such as a spouse, parent, fetus, or donor. For example, fetus observations in a mother's record. The focus of an observation could also be an existing condition, an intervention, the subject's diet, another observation of the subject, or a body structure such as tumor or implanted device. An example use case would be using the Observation resource to capture whether the mother is trained to change her child's tracheostomy tube. In this example, the child is the patient of record and the mother is the focus.",
"comment": "Typically, an observation is made about the subject - a patient, or group of patients, location, or device - and the distinction between the subject and what is directly measured for an observation is specified in the observation code itself ( e.g., \"Blood Glucose\") and does not need to be represented separately using this element. Use `specimen` if a reference to a specimen is required. If a code is required instead of a resource use either `bodysite` for bodysites or the standard extension [focusCode](https://hl7.org/fhir/extension-observation-focuscode.html).",
"min": 0,
"max": "1",
"base": {
"path": "Extension.value[x]",
"min": 0,
"max": "1"
},
"type": [
{
"code": "Reference",
"targetProfile": "http://hl7.org/fhir/4.0/StructureDefinition/profile-Resource|0.1.0"
},
{
"code": "Reference",
"targetProfile": "http://hl7.org/fhir/StructureDefinition/Resource"
}
],
"mapping": [
{
"identity": "rim",
"map": "N/A"
}
]
}
]
},
"differential": {
"element": [
{
"id": "Extension",
"path": "Extension",
"short": "R4: What the observation is about, when it is not about the subject of record (new)",
"definition": "R4: `Observation.focus` (new:Reference(Resource))",
"comment": "Element `Observation.focus` has a context of Observation.related based on following the parent source element upwards and mapping to `Observation`.\nElement `Observation.focus` has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).\nTypically, an observation is made about the subject - a patient, or group of patients, location, or device - and the distinction between the subject and what is directly measured for an observation is specified in the observation code itself ( e.g., \"Blood Glucose\") and does not need to be represented separately using this element. Use `specimen` if a reference to a specimen is required. If a code is required instead of a resource use either `bodysite` for bodysites or the standard extension [focusCode](https://hl7.org/fhir/extension-observation-focuscode.html).",
"min": 0,
"max": "*",
"base": {
"path": "Extension",
"min": 0,
"max": "*"
},
"isModifier": false
},
{
"id": "Extension.url",
"path": "Extension.url",
"min": 1,
"max": "1",
"base": {
"path": "Extension.url",
"min": 1,
"max": "1"
},
"fixedUri": "http://hl7.org/fhir/4.0/StructureDefinition/extension-Observation.focus"
},
{
"id": "Extension.value[x]",
"path": "Extension.value[x]",
"short": "What the observation is about, when it is not about the subject of record",
"definition": "The actual focus of an observation when it is not the patient of record representing something or someone associated with the patient such as a spouse, parent, fetus, or donor. For example, fetus observations in a mother's record. The focus of an observation could also be an existing condition, an intervention, the subject's diet, another observation of the subject, or a body structure such as tumor or implanted device. An example use case would be using the Observation resource to capture whether the mother is trained to change her child's tracheostomy tube. In this example, the child is the patient of record and the mother is the focus.",
"comment": "Typically, an observation is made about the subject - a patient, or group of patients, location, or device - and the distinction between the subject and what is directly measured for an observation is specified in the observation code itself ( e.g., \"Blood Glucose\") and does not need to be represented separately using this element. Use `specimen` if a reference to a specimen is required. If a code is required instead of a resource use either `bodysite` for bodysites or the standard extension [focusCode](https://hl7.org/fhir/extension-observation-focuscode.html).",
"min": 0,
"max": "1",
"base": {
"path": "Extension.value[x]",
"min": 0,
"max": "1"
},
"type": [
{
"code": "Reference",
"targetProfile": "http://hl7.org/fhir/4.0/StructureDefinition/profile-Resource|0.1.0"
},
{
"code": "Reference",
"targetProfile": "http://hl7.org/fhir/StructureDefinition/Resource"
}
]
}
]
}
}
Extension 
value[x] 
FHIR
FHIRsmith