An exam finding using pattern 3 described in the "Using Codes in Observation" Section

{
  "resourceType" : "Observation",
  "id" : "abdo-tender",
  "status" : "final",
  "category" : [{
    "coding" : [{
      "system" : "http://terminology.hl7.org/CodeSystem/observation-category",
      "code" : "exam",
      "display" : "Exam"
    }]
  }],
  "code" : {
    "coding" : [{
      "system" : "http://snomed.info/sct",
      "code" : "43478001",
      "display" : "Abdominal tenderness (finding)"
    }],
    "text" : "Abdominal tenderness"
  },
  "subject" : {
    "reference" : "Patient/example"
  },
  "encounter" : {
    "reference" : "Encounter/example"
  },
  "effectivePeriod" : {
    "start" : "2018-04-02T10:30:10+01:00"
  },
  "issued" : "2018-04-03T15:30:10+01:00",
  "valueBoolean" : true,
  "interpretation" : [{
    "coding" : [{
      "system" : "http://terminology.hl7.org/CodeSystem/v3-ObservationInterpretation",
      "code" : "A",
      "display" : "Abnormal"
    }],
    "text" : "Abnormal"
  }]
}