{

"resourceType": "Observation",
"id": "bmi-using-related",
"status": "final",
"category": [
  {
    "coding": [
      {
        "system": "http://terminology.hl7.org/CodeSystem/observation-category",
        "code": "vital-signs",
        "display": "Vital Signs"
      }
    ],
    "text": "Vital Signs"
  }
],
"code": {
  "coding": [
    {
      "system": "http://loinc.org",
      "code": "39156-5",
      "display": "Body mass index (BMI) [Ratio]"
    }
  ],
  "text": "BMI"
},
"subject": {
  "reference": "Patient/example"
},
"effectiveDateTime": "1999-07-02",
"valueQuantity": {
  "value": 16.2,
  "unit": "kg/m2",
  "system": "http://unitsofmeasure.org",
  "code": "kg/m2"
},
"derivedFrom": [
  {
    "reference": "Observation/bodyheight",
    "display": "Body Height"
  },
  {
    "reference": "Observation/example",
    "display": "Body Weight"
  }
],
"meta": {
  "tag": [
    {
      "system": "http://terminology.hl7.org/CodeSystem/v3-ActReason",
      "code": "HTEST",
      "display": "test health data"
    }
  ]
}

}