Records that the requester wants this order brought back to them if what it produces is abnormal.
An instruction recorded on the order, not a finding about a result. It is set when the order is
placed and applies to whatever the order eventually yields. Nothing about a value of true says any
result was abnormal, and a consumer must not read it as an abnormality marker -- Observation
interpretation codes are where that question is answered.
Whether the instruction fires is decided elsewhere, by a periodic review of what the order
produced. This element is the preference alone: it changes nothing by itself, and a consumer must
not infer from its presence that any review has run, that any result was abnormal, or that anyone
was notified. Where such a review does act, it does so by adding to the order's own note and to
the tasks filed against the order, not by writing back here.
Absent and false mean the same thing. A writer creates the extension only when switching the
instruction on and thereafter sets the value in place, so false occurs on orders where it was once
on. Read either as "not requested".
At most one per order. A reader encountering more than one should take the first.
Nothing acts on this instruction today. The review that would surface an abnormal result reads a
companion marker alongside this flag, and no writer produces that marker, so an order carrying
true records the preference and goes no further; that is tracked as FHIR-387. Treat the value as
the requester's stated preference alone, and never as evidence that a review ran or that a result
was abnormal.
Nexus EMR writes this today at
http://services.well.com/fhir/ServiceRequest/action-on-abnormal (FHIR-371): it is live in
stored ServiceRequest.extension values and in code, and is under migration to the canonical
declared here. Write the canonical; expect both until the migration completes, and match both
addresses exactly -- the pre-migration address carries a ServiceRequest path segment the canonical
does not, so a rule built on the whole address rather than its last segment will not reach it.
May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.
Comments
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.
Source of the definition for the extension code - a logical name or a URL.
Comments
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.
True when the requester asked to be brought an abnormal result
Definition
true when the requester asked for this order to be surfaced to them if what it produces is abnormal. false means not requested and carries nothing an absent extension does not; it exists so the instruction can be switched off in place.