What does CO 27 mean?

Coverage had ended on the date of service. Contractual obligation. The provider absorbs it and cannot bill the patient.

Why does CO 27 happen?

Coverage had terminated before the date of service.

What documentation wins a CO 27 appeal?

Evidence another plan was active, and a rebill to that payer.

CO 27 denial code description — what it means and how to appeal it

Q: Can you appeal CO 27?

Usually lost. Re-verify eligibility. If another plan was active, rebill that payer.

What CO 27 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. 27 also arrives as PR 27. 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 27, 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.

Coverage had terminated before the date of service.

What to do

Re-verify eligibility. If another plan was active, rebill that payer.

What actually wins it

The documentation, not the argument.

Evidence another plan was active, and a rebill to that payer.

The common mistake. Re-verify eligibility before writing this off. A termination date in the payer's system is sometimes wrong, and the patient often has other coverage.

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 27 description

Coverage had ended on the date of service. 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 27 denial code