X12 278 HCR01 (Action Code): Format, Values, and Testing Notes
It's tempting to model prior authorization as a binary outcome, but HCR01 supports a dozen-plus values, and the ones that get skipped in testing — pended, modified, cancelled — are exactly the ones that require the most careful handling in a real workflow.
HCR01 is a code value in the HCR segment of a 278 response that states the outcome of a prior authorization review — for example certified, modified, denied, or pended — and it is what downstream systems branch on to decide what happens next.
Valid code values
Example
HCR01 is A1 here, certifying the request in full. Synthetic test data.
Where this trips people up
Integration tests tend to hardcode a switch statement covering A1 and A4 and treat everything else as a fallback error. A6 (pended) in particular gets mishandled this way — it's not a terminal state, it means the payer hasn't decided yet, and code that treats it as a failure will show a denied authorization to a provider when the real answer is simply not available yet.