What Is HL7 v2 DG1-4? Diagnosis Description, Explained for Testers
DG1-4 looks redundant next to the text portion already sitting inside DG1-3, and that redundancy is exactly the point — it's also exactly where two systems can end up disagreeing about what a diagnosis actually is.
DG1-4 is a free-text field carrying the diagnosis description as a standalone value, separate from the text sub-component embedded in DG1-3. Many sending systems populate both with the same wording, but nothing in the message structure guarantees that — DG1-4 can legally carry different, more detailed, or entirely absent text.
What this field contains
Example
DG1-4 restates the diagnosis text independently of the description embedded inside DG1-3.
Where this trips people up
Downstream display logic frequently reads DG1-4 for the diagnosis label shown on a chart or worklist while billing logic reads the text sub-component of DG1-3 — and when a source system only populates one of the two, one side of the workflow shows a blank diagnosis name while the other works fine. Test messages where DG1-4 is empty but DG1-3's text sub-component is populated, and the reverse, to see which of your downstream consumers silently fail versus which fall back correctly.