CARC 15 denial code: meaning & whether to appeal (verified)
What CARC 15 means
The authorization number is missing, invalid, or does not apply to the billed services or provider.
Verbatim description from the official X12 Claim Adjustment Reason Codes list.
Classification
Denial class: prior authorization
Appealability verdict
Appealable — prior authorization
What to know
Check whether an authorization actually existed (wrong number, wrong provider on the auth, or payer mismatch are common), whether a retro-authorization path exists, and whether the payer met its own decision deadlines.