Reference·PR1 Segment·PR1-6
HL7 v2 Reference

HL7 v2 PR1-6 Field Guide: Procedure Type Codes and Common Mistakes

Jul 27, 2026 · 4 min read
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When an encounter has more than one PR1 segment, PR1-6 is the field that tells a downstream system which procedure was the primary one and which were secondary. Miss it, and a billing or reporting system has to guess — usually by picking whichever PR1 came first, which is not always correct.

Quick answer

PR1-6 is the sixth field of the HL7 v2 PR1 segment — the Procedure Type, a coded value classifying a procedure as primary, secondary, or another category, used to rank multiple procedures recorded for the same encounter.

Valid code values

P
Primary Procedure — the main procedure performed during the encounter
O
Other Procedure — a secondary or additional procedure performed alongside the primary one
blank
Unspecified — some sending systems omit this and rely on segment order alone, which is fragile

Example

Synthetic example Generated by Synthibase
PR1|1||47562^LAPAROSCOPIC CHOLECYSTECTOMY^CPT|LAPAROSCOPIC REMOVAL OF GALLBLADDER VIA FOUR SMALL ABDOMINAL INCISIONS|20260726103000|P||8842^REYES^MONICA^L^^^MD

PR1-6 carries P, marking this laparoscopic cholecystectomy as the primary procedure for the encounter. Synthetic record — not a real patient.

Where this trips people up

Some sending systems only ever populate PR1-6 for the primary procedure and leave it blank on every secondary PR1 segment, rather than explicitly marking them as Other. A receiving system that treats a blank value as "also primary" instead of "not specified" can end up billing or reporting two procedures as co-primary when only one actually was. Test messages with multiple PR1 segments should include at least one where the type code is deliberately blank on a secondary procedure, so you can confirm the downstream logic doesn't default it into primary status.

HL7 v2 PR1 Segment Guide: Fields, Format, and Testing Gotchas
How to Reduce Claim Denials Through Better Pre-Submission Testing
How to Write EDI Test Cases That Actually Catch Go-Live Failures
Test primary vs. secondary procedure ranking
Synthibase generates synthetic multi-procedure encounters with correctly and incorrectly populated PR1-6 type codes, so you can verify your ranking logic handles both cases.
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