What does CO 204 mean?

Not covered under the patient’s current benefit plan. Contractual obligation. The provider absorbs it and cannot bill the patient.

Why does CO 204 happen?

The service is excluded from the patient's current benefit plan.

What documentation wins a CO 204 appeal?

An ABN signed before the service was delivered.

CO 204 denial code description — what it means and how to appeal it

Q: Can you appeal CO 204?

Usually lost. Check for an ABN or a patient waiver, then bill the patient or write off.

What CO 204 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. 204 also arrives as PR 204. 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 PR 204, read that page instead.

Is it worth appealing?

Usually lost. Recoverable only with unusual evidence. Triage by dollar value.

Why it fires

In the order we see it.

The service is excluded from the patient's current benefit plan.

What to do

Check for an ABN or a patient waiver, then bill the patient or write off.

What actually wins it

The documentation, not the argument.

An ABN signed before the service was delivered.

The common mistake. Do not bill the patient on a Medicare claim without a valid ABN signed in advance.

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 204 description

Not covered under the patient’s current benefit plan. 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
N30	The patient was not eligible for this particular service on that date. That is narrower than not being covered at all, and the difference matters.

CO 204 denial code