{
  "resourceType": "StructureDefinition",
  "id": "NHSHC-Observation",
  "url": "https://fhir.nhs.uk/StructureDefinition/NHSHC-Observation",
  "version": "0.1.0",
  "name": "NHSHCObservation",
  "title": "NHSHC Observation",
  "status": "draft",
  "date": "2026-06-23",
  "publisher": "NHS England",
  "description": "Derived profile from UKCore-Observation for NHS Health Check Online. Enforces status=final and requires one of: value[x], dataAbsentReason, component, or hasMember. Supports vital signs, labs, social history, and physical activity observations.",
  "fhirVersion": "4.0.1",
  "kind": "resource",
  "abstract": false,
  "type": "Observation",
  "baseDefinition": "https://fhir.hl7.org.uk/StructureDefinition/UKCore-Observation",
  "derivation": "constraint",
  "differential": {
    "element": [
      {
        "id": "Observation",
        "path": "Observation",
        "constraint": [
          {
            "key": "nhshc-obs-1",
            "severity": "error",
            "human": "At least one of value[x], dataAbsentReason, component, or hasMember must be present.",
            "expression": "value.exists() or dataAbsentReason.exists() or component.exists() or hasMember.exists()"
          }
        ]
      },
      {
        "id": "Observation.status",
        "path": "Observation.status",
        "min": 1,
        "fixedCode": "final"
      },
      {
        "id": "Observation.category",
        "path": "Observation.category",
        "min": 1
      },
      {
        "id": "Observation.code",
        "path": "Observation.code",
        "min": 1,
        "binding": {
          "strength": "extensible",
          "valueSet": "http://hl7.org/fhir/ValueSet/observation-codes"
        }
      },
      {
        "id": "Observation.subject",
        "path": "Observation.subject",
        "min": 1,
        "type": [
          {
            "code": "Reference",
            "targetProfile": [
              "https://fhir.hl7.org.uk/StructureDefinition/UKCore-Patient"
            ]
          }
        ]
      },
      {
        "id": "Observation.encounter",
        "path": "Observation.encounter",
        "min": 1,
        "type": [
          {
            "code": "Reference",
            "targetProfile": [
              "https://fhir.nhs.uk/StructureDefinition/NHSHC-Encounter"
            ]
          }
        ]
      },
      {
        "id": "Observation.effective[x]",
        "path": "Observation.effective[x]",
        "min": 1
      },
      {
        "id": "Observation.performer",
        "path": "Observation.performer",
        "min": 1,
        "type": [
          {
            "code": "Reference",
            "targetProfile": [
              "https://fhir.hl7.org.uk/StructureDefinition/UKCore-Organization",
              "https://fhir.hl7.org.uk/StructureDefinition/UKCore-Practitioner"
            ]
          }
        ]
      }
    ]
  }
}