Reference·PID Segment·PID-8
HL7 v2 Reference

HL7 v2 PID-8 (Administrative Sex): Format, Values, and Testing Notes

Jul 27, 2026 · 4 min read
PID-1 →

Most integrations are built and tested assuming PID-8 only ever contains M or F — until an upstream feed sends O, U, A, or N and the message gets silently rejected or mis-mapped downstream.

Quick answer

PID-8 is the eighth field of the HL7 v2 PID segment — it carries the patient’s administrative sex as a coded value, used for demographic and billing purposes across ADT, ORU, and other message types.

Valid code values

M
Male
F
Female
O
Other
U
Unknown
A
Ambiguous
N
Not applicable

Example

Synthetic example Generated by Synthibase 
PID|1||847213609^^^HOSP^MR||GARCIA^ELENA^M||19870314|F|||482 OAK ST^^DENVER^CO^80202||3035550142|||M|

The 8th field (F) marks the patient as female. Synthetic patient — not a real person.

Where this trips people up

Systems built to expect only M or F will reject or mis-map O/U/A/N values coming from upstream feeds. This is exactly the kind of edge case that passes a happy-path test suite and then fails on real go-live data — worth testing explicitly before launch, not discovering in production.

→
HL7 v2 PID Segment Guide: Fields, Format, and Testing Gotchas
 →
How to Write EDI Test Cases That Actually Catch Go-Live Failures
 →
Synthetic Patient Data: Complete Guide for Software Testing
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Synthibase generates synthetic PID segments covering every administrative sex code — including the edge cases most test suites miss.
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