Reference·X12 278·HCR
X12 278 Reference

Testing X12 278 HCR: The Fields Your System Actually Needs to Handle

Jul 27, 2026 · 6 min read

A 278 response file can be perfectly well-formed X12 and still be wrong in a way that matters: the certification number populated, the segment counts balanced, and the action code sitting on a value nobody built a branch for, so the request quietly stalls in a queue instead of routing to the right team.

Quick answer

HCR is the segment in a 278 response transaction that carries the actual outcome of a prior authorization review — whether the request was certified, modified, denied, or pended — along with the certification number the requester needs for downstream claims.

The elements that actually matter in practice

HCR01 →
Action Code — the review outcome — certified, modified, denied, pended, and several less common variants
HCR02 →
Certification Number — the payer-assigned number the requester later cites on the claim; often blank when the request is denied
HCR03
Free-form message — a short human-readable note, sometimes the only place a denial reason shows up in plain text
Where it sits
Loop 2000E / service level — HCR can repeat per service line, so one 278 response can carry different outcomes for different requested services

Example

Synthetic example Generated by Synthibase
HCR*A1*AUTH88213221*Approved as submitted

A synthetic 278 response certifying the request in full and returning an authorization number the requester will later reference on the matching 837 claim. Synthetic test data.

Where this trips people up

Most test suites are built around the happy path — HCR01 equal to A1, a populated certification number, done. But HCR can repeat once per service line within a single 278 response, so a request covering three procedures can come back with one certified, one modified, and one denied in the same transaction. Parsers that grab the first HCR segment and assume it applies to the whole request silently misreport partial denials as full approvals.

X12 278 Prior Authorization: Format, Fields, and Testing Guide
How to Validate X12 EDI Files Before Payer Submission
Test every 278 outcome, not just the approval
Synthibase generates synthetic 278 responses across the full range of HCR action codes — including mixed-outcome, multi-service responses — so authorization handling gets tested against denials and partial approvals before go-live, not after.
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This page is written independently by Synthibase for testing and informational purposes. It is not an official publication of HL7 International or X12/Washington Publishing Company, and is not a substitute for reviewing the official standard or your trading partner's companion guide. See our Terms of Service for full legal terms.