AppealHoundBy Vantar Group
Denial code · updated 22 October 2026

CO 27: Coverage Terminated

Coverage had ended on the date of service.

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

Usually lost CO PR 27

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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.

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  1. Coverage had terminated before the date of service.

How to Appeal CO 27, Step by Step

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

  1. 1Step 1: Read the remark code. Find the remark code printed next to CO 27 on the 835 or EOB. It says what the payer wants back. The usual ones are N30.
  2. 2Step 2: Find the cause. Match the denial to one of the cause in Why It Fires above, and fix that one.
  3. 3Step 3: Take the first action. Re-verify eligibility. If another plan was active, rebill that payer.
  4. 4Step 4: Attach the documentation. Evidence another plan was active, and a rebill to that payer.
  5. 5Step 5: Send the appeal before the deadline. Send it to the payer with the claim, the denial and the documentation, inside the payer's appeal window. See what an appeal letter must contain and the filing limits by 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.

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CO 27 description

Coverage had ended on the date of service.

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.

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.

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.

RemarkWhat it means
N30The patient was not eligible for this particular service on that date. That is narrower than not being covered at all, and the difference matters.

Related Codes

Your Questions Answered

What does CO 27 mean?

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

Can you appeal CO 27?

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

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.

How do I appeal a CO 27 denial?

Step 1: Read the remark code. Find the remark code printed next to CO 27 on the 835 or EOB. It says what the payer wants back. Step 2: Find the cause. Match the denial to one cause: Coverage had terminated before the date of service. Step 3: Take the first action. Re-verify eligibility. If another plan was active, rebill that payer. Step 4: Attach the documentation. Evidence another plan was active, and a rebill to that payer. Step 5: Send the appeal before the deadline. Send it to the payer with the claim, the denial and the documentation, inside the payer's appeal window.

Most searched: CO 97 · CO 96 · OA 23 · PR 204 · CO 109 · CO 197 · CO 45 · CO 50

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