What does CO 22 mean?

Another plan should pay first. Contractual obligation. The provider absorbs it and cannot bill the patient.

Can you appeal CO 22?

Fix and resubmit. Get the primary EOB and rebill as secondary. Not an appeal.

Why does CO 22 happen?

Another plan is primary for this patient on this date of service.

What documentation wins a CO 22 appeal?

The primary payer's EOB, submitted with the claim as secondary.

CO 22 denial code description — what it means and how to appeal it

What CO 22 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.

The same code, a different prefix. 22 also arrives as OA 22. The reason for the denial is the same. The prefix decides who pays for it, so the next step is not the same. If your remit says OA 22, read that page instead.

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.

Another plan is primary for this patient on this date of service.

What to do

Get the primary EOB and rebill as secondary. Not an appeal.

What actually wins it

The documentation, not the argument.

The primary payer's EOB, submitted with the claim as secondary.

The common mistake. Do not appeal this. It is a rebill as secondary, and appealing delays the money.

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.

CO 22 description

Another plan should pay first. 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.

This is our plain-English wording, not the official X12 text. X12 asserts copyright over the published descriptions, so we write our own and say what it means for the money rather than restating the code.

The remark code beside it

The adjustment code says the claim was reduced. The remark code printed next to it says why, and it is the one that tells you what to send back.

Remark	What it means
MA04	This was billed as a secondary claim and the payer has no record of what the primary did with it.
N522	This duplicates a claim that is already crossing over from another payer.

CO 22 denial code