A clinician's own display title for one diagnostic report, replacing the title a reader would
otherwise compute from the report's code.
Not a second code, and not a coded value.code states what was measured and is what a
clinical reader, a query or a mapping uses. This is free text one person chose for one report, and
nothing should be inferred from it.
Absent means the report has not been renamed -- not that it has no title. A reader computes the
title in that case: the report's code.text where it has one, otherwise the display values of
code.coding joined in order, otherwise a generic placeholder. A consumer that renders this element
with no fallback shows a blank heading on almost every report. Clearing a title removes the
extension rather than writing an empty string, so a reader that treats present-but-blank as a title
renders an empty heading; trim the value and fall back when nothing is left.
At most one per report. A writer replaces the existing occurrence rather than adding a second,
and a reader encountering more than one should take the first.
Nexus EMR writes this today at http://services.well.com/fhir/report-display-title
(FHIR-371): it is live in stored DiagnosticReport.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 rather than deriving one from the other.
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.
The title a clinician gave this report, trimmed of surrounding whitespace. Free text with no coded meaning. An empty or whitespace-only value is not written -- the extension is removed instead -- so a reader that finds one should treat it as absent and compute the title from code.