{
  "resourceType": "CodeSystem",
  "status": "draft",
  "content": "complete",
  "name": "DiagnosticReportSentDownstreamCS",
  "id": "diagnostic-report-sent-downstream",
  "title": "Diagnostic Report Sent Downstream Tag CodeSystem",
  "description": "Records that the report ingest has completed its downstream handoff for this report. Carried as a\ntag on `DiagnosticReport.meta.tag`, where this is the tag's `system`.\n\n**A tag, not an extension.** The address identifies the `system` of a `Coding` in `meta.tag`, which\nis why it is declared as a code system. The vocabulary is the unusual part: the codes are the\nliteral strings `true` and `false`, the writer's rendering of a boolean.\n\n**It is an idempotency marker, not provenance.** Its purpose is to stop a re-sent or replayed report\nbeing handed on twice, and to let a duplicate that was never handed on be handed on now. A consumer\nthat needs to know what actually happened to a report should read `AuditEvent` or `Provenance`.\n\n**`true` does not guarantee anything received the report.** The handoff is a custom operation on\n`DiagnosticReport` that the receiving server advertises in its `CapabilityStatement`; that operation\nis not part of this specification. Where the server does not advertise it, the handoff is skipped\nrather than failed, and the tag is written all the same. So `true` means the ingest reached the end\nof its handoff step for this report, and no more than that. A handoff that fails outright leaves the\nreport untagged so it can be retried, which is why the absent state is the meaningful one.\n\n**`false` is representable but is not written.** The vocabulary is closed by the boolean it is\nrendered from, so both codes are listed; only `true` is emitted. Read `false` exactly as an absent\ntag, compare case-insensitively, and treat anything that is not `true` as not handed on rather than\nas an error.\n\n**One tag per system, and this system carries one fact.** A writer replaces any existing tag with\nthis system rather than adding a second. The parallel record of the provincial send is a separate\nsystem, `https://fhir.apps.health/CodeSystem/diagnostic-report-acdr-sent`, precisely so that the two\ncan be held at once.\n\n**Nexus EMR writes this today at\n`http://services.well.com/fhir/tags/diagnostic-reports/sent-downstream` (FHIR-371)**: it is live in\nstored `DiagnosticReport.meta.tag` codings and in code, and is under migration to the canonical\ndeclared here. Write the canonical; expect both until the migration completes, and match both\naddresses exactly rather than deriving one from the other.",
  "url": "https://fhir.apps.health/CodeSystem/diagnostic-report-sent-downstream",
  "concept": [
    {
      "code": "true",
      "display": "Handed on",
      "definition": "The ingest completed its downstream handoff step for this report. Not a guarantee that a downstream system received it."
    },
    {
      "code": "false",
      "display": "Not handed on",
      "definition": "The ingest has not completed its downstream handoff for this report. Representable but not written by Nexus EMR; a reader should treat it exactly as an absent tag."
    }
  ],
  "experimental": false,
  "caseSensitive": false,
  "count": 2
}