Denial code

CO 15

The authorisation number is missing, invalid, or does not match.

Fix and resubmit CO

What CO 15 means

CO — Contractual obligation — the provider absorbs it and cannot bill the patient.

So the balance cannot move to the patient. Either the appeal recovers it or the practice absorbs it. That makes the appeal decision the whole decision on this line.

Is it worth appealing?

Fix and resubmit. This is a correction, not an appeal. Appealing burns the deadline.

Why it fires

In the order we see it.

  1. The authorisation number is missing, mistyped, or belongs to a different episode.

What to do

Correct the auth number and resubmit. This is not an appeal.

What actually wins it

The documentation, not the argument.

The correct authorisation number and its date range.

The common mistake. Do not appeal. Correct the number and resubmit.

Where this comes from. This is our own reading of the code, not the payer's and not a copy of the standards text. We classify it from how these denials actually resolve. Where we are unsure, we say so rather than guessing.

Related codes

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