An example of an alert message

{
  "resourceType" : "Communication",
  "id" : "example",
  "text" : {
    "status" : "generated",
    "div" : "<div xmlns=\"http://www.w3.org/1999/xhtml\">Patient has very high serum potassium</div>"
  },
  "identifier" : [{
    "type" : {
      "text" : "Paging System"
    },
    "system" : "urn:oid:1.3.4.5.6.7",
    "value" : "2345678901"
  }],
  "instantiatesUri" : ["http://example.org/hyperkalemia"],
  "partOf" : [{
    "display" : "Serum Potassium Observation"
  }],
  "status" : "completed",
  "category" : [{
    "coding" : [{
      "system" : "http://acme.org/messagetypes",
      "code" : "Alert"
    }],
    "text" : "Alert"
  }],
  "medium" : [{
    "coding" : [{
      "system" : "http://terminology.hl7.org/CodeSystem/v3-ParticipationMode",
      "code" : "WRITTEN",
      "display" : "written"
    }],
    "text" : "written"
  }],
  "subject" : {
    "reference" : "Patient/example"
  },
  "encounter" : {
    "reference" : "Encounter/example"
  },
  "sent" : "2014-12-12T18:01:10-08:00",
  "received" : "2014-12-12T18:01:11-08:00",
  "recipient" : [{
    "reference" : "Practitioner/example"
  }],
  "sender" : {
    "reference" : "Device/f001"
  },
  "payload" : [{
    "contentCodeableConcept" : {
      "text" : "Patient 1 has a very high serum potassium value (7.2 mmol/L on 2014-Dec-12 at 5:55 pm)"
    }
  },
  {
    "contentReference" : {
      "display" : "Serum Potassium Observation"
    }
  }]
}