Requisition Form Answers Extension¶
| Canonical | ../StructureDefinition/nexus-requisition-answers |
|---|---|
| Status | draft · 1.26.0 |
| Base | Extension (constraint) |
| Context | ServiceRequest (element) |
| Source | FSH · JSON |
The keyed answers written onto a laboratory requisition: the dependent inputs printed beside individual boxes, the check-one category choices, and the insured / uninsured billing choices.
Overview
One keyed list, not three shapes. Every entry is "an answer written on the form", and its key
says which question it answers. A consumer learns one shape and reads all three kinds.
Why not a QuestionnaireResponse. Not because of separability -- a CONTAINED
QuestionnaireResponse has no independent identity, cannot be deleted or versioned on its own, and
travels with its parent, which is exactly the inseparability a requisition needs. The reason is that
there is no Questionnaire for it to reference: this guide does not enumerate the provincial form's
keys, so a response would carry the same opaque keys with its questionnaire element empty, and a
response with no questionnaire cannot be interpreted beyond its own display text. What the contained
shape would genuinely buy is TYPED answers -- a category: index would be an integer rather than a
decimal held as a string -- and that gain is real. Publishing a Questionnaire for the form is what
would change this answer.
Reading a key
A key is a prefix naming the kind of question, followed by the form's own identifier for the specific input, category or billing choice:
| prefix | what the answer answers | what the value holds |
|---|---|---|
mod: |
a dependent input printed beside a single box | the text typed onto the ruled line, or the option circled |
category: |
a section's check-one category | a decimal index into the printed option list, as a string |
billing: |
a section's insured / uninsured choice | the chosen option's value |
The identifiers after the prefix are the form's own and are not enumerated here. They belong to a particular revision of a particular provincial requisition, which is republished on its own cadence; a copy inside this specification would be a snapshot that starts drifting the day it is written. A consumer should treat an unrecognised key as an answer to a question it does not render, and must not fail on one.
Values are strings, including the numeric one. A category: value is a positional index, held
as a decimal string, and it is meaningful only against the form revision that produced it. It is
not a code and must not be read as one.
An empty list is not written. A producer emits the extension only when at least one answer carries both a key and a value, so a stored entry is never blank.
At most one, on the order only. The answers are not echoed onto the DiagnosticReport the
requisition eventually produces.