{
  "resourceType": "StructureDefinition",
  "id": "observation-focal-subject",
  "extension": [
    {
      "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
      "valueCode": "oo"
    },
    {
      "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm",
      "valueInteger": 1
    }
  ],
  "url": "http://hl7.org/fhir/StructureDefinition/observation-focal-subject",
  "name": "focal-subject",
  "title": "Focal Subject",
  "status": "draft",
  "date": "2015-03-02",
  "publisher": "Health Level Seven, Inc. - FHIR WG",
  "contact": [
    {
      "telecom": [
        {
          "system": "url",
          "value": "HL7"
        }
      ]
    }
  ],
  "description": "The focus of an observation when not the patient of record  (i.e. different from Observation.subject).   For example, the focal subject may be a fetus, or a donor.",
  "fhirVersion": "3.0.1",
  "mapping": [
    {
      "identity": "rim",
      "uri": "http://hl7.org/v3",
      "name": "RIM Mapping"
    }
  ],
  "kind": "complex-type",
  "abstract": false,
  "contextType": "resource",
  "context": [
    "Observation"
  ],
  "type": "Extension",
  "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension",
  "derivation": "constraint",
  "differential": {
    "element": [
      {
        "id": "Extension",
        "path": "Extension",
        "short": "Focal Subject",
        "definition": "The focus of an observation when not the patient of record  (i.e. different from Observation.subject).   For example, the focal subject may be a fetus, or a donor.",
        "comment": "Use Observation.specimen element to describe the specimen.  Only used if not implicit in code found in Observation.code.",
        "min": 0,
        "max": "1",
        "isModifier": true
      },
      {
        "id": "Extension.extension",
        "path": "Extension.extension",
        "max": "0"
      },
      {
        "id": "Extension.url",
        "path": "Extension.url",
        "type": [
          {
            "code": "uri"
          }
        ],
        "fixedUri": "http://hl7.org/fhir/StructureDefinition/observation-focal-subject"
      },
      {
        "id": "Extension.valueCodeableConcept",
        "path": "Extension.valueCodeableConcept",
        "type": [
          {
            "code": "CodeableConcept"
          }
        ],
        "binding": {
          "extension": [
            {
              "url": "http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName",
              "valueString": "FocalSubject"
            }
          ],
          "strength": "example",
          "description": "Codes for observation targets.  Derived from both HL7 v3 and SNOMED CT code systems",
          "valueSetReference": {
            "reference": "http://hl7.org/fhir/ValueSet/focal-subject"
          }
        }
      }
    ]
  }
}