{
  "resourceType": "Questionnaire",
  "status": "active",
  "item": [
    {
      "linkId": "lipid",
      "text": "Lipid Panel",
      "type": "group",
      "item": [
        {
          "linkId": "lipid-tc",
          "code": [
            {
              "system": "http://loinc.org",
              "code": "2093-3"
            }
          ],
          "text": "Total cholesterol (mg/dL)",
          "type": "decimal",
          "extension": [
            {
              "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-unit",
              "valueCoding": {
                "system": "http://unitsofmeasure.org",
                "code": "mg/dL",
                "display": "mg/dL"
              }
            }
          ]
        },
        {
          "linkId": "lipid-hdl",
          "code": [
            {
              "system": "http://loinc.org",
              "code": "2085-9"
            }
          ],
          "text": "HDL cholesterol (mg/dL)",
          "type": "decimal",
          "extension": [
            {
              "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-unit",
              "valueCoding": {
                "system": "http://unitsofmeasure.org",
                "code": "mg/dL",
                "display": "mg/dL"
              }
            }
          ]
        },
        {
          "linkId": "lipid-tg",
          "code": [
            {
              "system": "http://loinc.org",
              "code": "2571-8"
            }
          ],
          "text": "Triglycerides (mg/dL)",
          "type": "decimal",
          "extension": [
            {
              "url": "http://hl7.org/fhir/StructureDefinition/questionnaire-unit",
              "valueCoding": {
                "system": "http://unitsofmeasure.org",
                "code": "mg/dL",
                "display": "mg/dL"
              }
            }
          ]
        },
        {
          "linkId": "lipid-ldl",
          "code": [
            {
              "system": "http://loinc.org",
              "code": "13457-7"
            }
          ],
          "text": "LDL cholesterol, calculated (mg/dL; blank when triglycerides are 400 or more)",
          "type": "decimal",
          "readOnly": true,
          "extension": [
            {
              "url": "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-calculatedExpression",
              "valueExpression": {
                "language": "text/fhirpath",
                "expression": "iif((%resource.item.where(linkId='lipid').item.where(linkId='lipid-tg').answer.valueDecimal) < 400, ((%resource.item.where(linkId='lipid').item.where(linkId='lipid-tc').answer.valueDecimal) - (%resource.item.where(linkId='lipid').item.where(linkId='lipid-hdl').answer.valueDecimal) - ((%resource.item.where(linkId='lipid').item.where(linkId='lipid-tg').answer.valueDecimal) / 5)).round(0), {})"
              }
            }
          ]
        }
      ]
    }
  ]
}