An "ask at order" response using the datetime datetype for the result value

{
  "resourceType": "Observation",
  "id": "date-lastmp",
  "text": {
    "status": "generated",
    "div": "<div xmlns=\"http://www.w3.org/1999/xhtml\"><p><b>Generated Narrative: Observation</b><a name=\"date-lastmp\"> </a></p><div style=\"display: inline-block; background-color: #d9e0e7; padding: 6px; margin: 4px; border: 1px solid #8da1b4; border-radius: 5px; line-height: 60%\"><p style=\"margin-bottom: 0px\">Resource Observation &quot;date-lastmp&quot; </p></div><p><b>status</b>: final</p><p><b>category</b>: AOE <span style=\"background: LightGoldenRodYellow; margin: 4px; border: 1px solid khaki\"> (<a href=\"http://terminology.hl7.org/3.1.0/CodeSystem-observation-category.html\">Observation Category Codes</a>#survey &quot;Survey&quot;)</span></p><p><b>code</b>: Date last menstrual period <span style=\"background: LightGoldenRodYellow; margin: 4px; border: 1px solid khaki\"> (<a href=\"https://loinc.org/\">LOINC</a>#8665-2)</span></p><p><b>subject</b>: <a href=\"patient-example-b.html\">Patient/pat2</a> &quot;Duck DONALD&quot;</p><p><b>effective</b>: 2016-01-24</p><p><b>value</b>: 2016-12-30</p></div>"
  },
  "status": "final",
  "category": [
    {
      "coding": [
        {
          "system": "http://terminology.hl7.org/CodeSystem/observation-category",
          "code": "survey",
          "display": "Survey"
        }
      ],
      "text": "AOE"
    }
  ],
  "code": {
    "coding": [
      {
        "system": "http://loinc.org",
        "code": "8665-2",
        "display": "Date last menstrual period"
      }
    ],
    "text": "Date last menstrual period"
  },
  "subject": {
    "reference": "Patient/pat2"
  },
  "effectiveDateTime": "2016-01-24",
  "valueDateTime": "2016-12-30"
}