Requisition Therapeutic Drug Monitoring Extension¶
| Canonical | ../StructureDefinition/nexus-requisition-tdm |
|---|---|
| Status | draft · 1.26.0 |
| Base | Extension (constraint) |
| Context | ServiceRequest (element) |
| Source | FSH · JSON |
One therapeutic-drug-monitoring block on a laboratory requisition: the monitored drug and the collection, last-dose and next-dose times a serum level must be interpreted against.
Overview
It repeats, once per block. The printed requisition rules two drug-monitoring blocks. Each block a clinician filled in is written as its own occurrence of this extension, in the order the form prints them. A consumer that reads only the first occurrence reads the first block correctly.
The three times are four-digit 24-hour clock readings (HHMM) held as strings, not FHIR time
or dateTime values. They carry no date and no timezone: the clinician typed a wall-clock reading,
and this preserves it as typed. Where a real collection instant is needed, read
collection.collectedDateTime on the Specimen contained in the requisition, which is a
fully-qualified zoned dateTime.
Every part is optional; an empty block is not written. A producer emits an occurrence only when at least one of the four boxes was filled in, so an occurrence always carries something. A block with a drug and a collection time but no dose times is an ordinary partial entry, not an error.
It is on the order, and only on the order. The monitoring times are not echoed onto the
DiagnosticReport the requisition eventually produces; a consumer interpreting a level has to read
them from the order.