NTE-2 in HL7 v2: A Field Guide to Source of Comment
NTE-2 answers a question receiving systems care about a lot more than test suites usually do: did this note come from the patient, from a lab tech, or from the ordering provider - because a lot of downstream routing and display logic branches on exactly that.
NTE-2 is a coded field indicating who or what produced the note carried in NTE-3. Common uses include marking a comment as coming from an ancillary department such as a lab, from the ordering provider, or from the patient directly, and systems often display or route notes differently depending on which source they came from.
What this field contains
Example
A synthetic NTE segment with source code P for patient-originated commentary, following an OBX result.
Where this trips people up
It is easy to build a test suite where every NTE-2 value is the same ancillary-department code because that is the scenario a lab interface happens to produce most often. When a patient-sourced or provider-sourced note eventually arrives in production, any downstream logic that treats source differently - flagging patient-reported notes for clinical review, say - never got a single test case that exercised it. If your generator only ever produces one source value, that branch is effectively untested.