{
  "resourceType": "Observation",
  "id": "demo-obs-pef-1",
  "status": "final",
  "code": {
    "coding": [
      {
        "system": "http://loinc.org",
        "code": "19935-6",
        "display": "Maximum expiratory gas flow Respiratory system airway by Peak flow meter"
      }
    ]
  },
  "subject": {
    "reference": "Patient/demo-patient-1"
  },
  "effectiveDateTime": "2018-04-11",
  "valueQuantity": {
    "value": 391,
    "system": "http://unitsofmeasure.org",
    "code": "L/min"
  },
  "referenceRange": [
    {
      "low": {
        "value": 368,
        "system": "http://unitsofmeasure.org",
        "code": "L/min"
      },
      "text": "Personal best peak flow 460 L/min"
    }
  ]
}