Official CARC description: “The authorization number is missing, invalid, or does not apply to the billed services or provider.” Here’s what it actually means, why it fires, and how to get the claim paid.
An auth number is on the claim but doesn't match — wrong format, wrong provider, wrong CPT, or wrong dates. Sibling of CO 197 with a data-matching flavor.
Liability group: CO = Contractual Obligation — the provider absorbs it — the amount cannot be billed to the patient. If the denial is wrong, the money is recovered by correcting or appealing the claim, not by balance-billing.
Pull the auth from the portal; compare every field to the claim
Simple mismatch: corrected claim with aligned data
CPT changed intra-procedure: request an auth amendment with the op note
Group/rendering NPI issues: ask the payer which NPI the auth binds to
Appeal with the auth documentation when the service was genuinely authorised — payers hold these to matching rules their own reps often misquote. Get the binding rules in writing.
Fill in the denial facts — use placeholders, never real patient data (the letter keeps [PATIENT NAME]-style fields so you can merge real details privately). A payer-ready draft with an enclosure checklist comes back in ~20 seconds.
Your appeal letter draft will appear here.
The authorization number is missing, invalid, or does not apply to the billed services or provider. In practice: An auth number is on the claim but doesn't match — wrong format, wrong provider, wrong CPT, or wrong dates. Sibling of CO 197 with a data-matching flavor.
CO stands for Contractual Obligation — the provider absorbs it — the amount cannot be billed to the patient. If the denial is wrong, the money is recovered by correcting or appealing the claim, not by balance-billing.
Appeal with the auth documentation when the service was genuinely authorised — payers hold these to matching rules their own reps often misquote. Get the binding rules in writing.