What does denial code CO-27 mean?

CO-27 means the claim was denied because the patient's insurance coverage had already terminated before the date of service was rendered. The payer's records show the policy was inactive on the DOS. This can occur because the patient lost employer coverage, failed to pay premiums, voluntarily canceled, or because the payer applied a retroactive termination. CO-27 is a contractual denial — the provider cannot collect the contractual adjustment from the patient, but may be able to bill the patient for the full charge if coverage was genuinely absent and the patient was notified.

Can I bill the patient after a CO-27 denial?

It depends. If the patient's coverage was genuinely terminated before the date of service, the patient is responsible for the claim because they received care without active insurance. You can bill the patient for the amount you would normally collect under the contract. However, if you verified eligibility at the time of service and the payer's retroactive termination is disputed by the patient, hold the claim while the patient resolves the coverage dispute. For Medicare patients, a valid Advance Beneficiary Notice (ABN) must be on file to bill the patient. Always check for secondary coverage (Medicaid, COBRA, another employer plan) before billing the patient directly.

What is a retroactive termination and how does it affect CO-27?

A retroactive termination occurs when a payer terminates coverage effective on a past date — for example, terminating coverage back to the 1st of the prior month because the patient's employer did not pay premiums or the employee separation was processed late. If a retro-termination is applied to a date before your service, the payer will deny all claims for that period with CO-27, even if your eligibility check at the time of service showed active coverage. When you receive CO-27 on a claim where you confirmed eligibility at the time of service, ask the payer specifically whether a retroactive termination was processed and when — this is your key to a successful appeal.

How is CO-27 different from CO-22?

CO-22 means another payer should have been billed first — the patient has coverage, but with a different plan in the primary position. CO-27 means the patient had no active coverage at all on the date of service — the policy ended before the claim was incurred. CO-22 is always fixable by resequencing and billing the correct primary. CO-27 may or may not be fixable — it depends on whether the termination date is accurate, whether a retroactive error was made, or whether other coverage existed.

CO-27 Denial Code: Coverage Terminated — Fix

CO-27 in plain English

CO-27 means the payer says the patient's coverage had already ended before the date of service. This may be accurate (the patient lost coverage and you weren't notified), or it may be a data error — specifically a retroactive termination where the payer backdated the end of coverage to a date before your service. Call the payer to confirm the exact termination date, compare it to your eligibility verification timestamp, and then decide whether to appeal (if the termination date is wrong), bill the patient (if coverage was genuinely lapsed), or check for secondary coverage.

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Always get the exact termination date from the payer before acting

The ERA often says only "coverage terminated." You need the exact date coverage ended. Call provider services and ask: "What is the exact coverage termination date for member [ID]?" If that date is after your DOS, the denial was issued in error and you have a strong appeal. If it's before your DOS, ask whether a retroactive termination was applied and when it was processed.

3 scenarios that generate CO-27

The response is different for each — identify yours first

1

Payer data error — coverage was active on DOS

Your eligibility verification confirmed active coverage, but the payer issued CO-27 due to a processing delay, a system error, or a retroactive termination that was reversed or contested. The most recoverable scenario.

Fix: Appeal with eligibility proof and verification timestamp

2

Retroactive termination — valid but backdated

Coverage was terminated retroactively to a date before your service — often because the patient lost employment, didn't pay premiums, or the employer processed separation late. Your eligibility check showed active coverage at the time of service, but the payer subsequently backdated the termination. Patient is generally responsible; advise the patient to appeal the retro-term with the payer or insurer.

Fix: Bill patient; advise patient to contest retro-term

3

Coverage lapsed before DOS — accurate denial

The patient's coverage genuinely ended before the date of service — they did not renew, voluntarily canceled, or lost coverage — and you did not verify eligibility before the service. No grounds to appeal; the patient is responsible for the bill.

Fix: Bill patient; check for secondary coverage first

Step-by-Step Response

What to do when you receive CO-27

Call the payer and get the exact termination date

Contact the payer's provider services line. Ask for the exact date coverage terminated for this member. Ask specifically: "Was this a prospective or retroactive termination?" and "When was the termination processed in your system?" Document the agent's name, call date, and reference number. The exact termination date is the single most important piece of information for everything that follows.
Compare the termination date to your eligibility verification record

Pull your eligibility verification record for this patient on or before the date of service. If your AVS response showed active coverage and the termination was applied retroactively after your service date, you have strong grounds for an appeal. Print or save the eligibility response with its timestamp — this is your primary appeal evidence.
If appealing — submit with eligibility verification proof

File a formal appeal with: (a) a copy of your eligibility verification response showing active coverage on the DOS, (b) the date and time the verification was run, (c) a statement noting that the service was rendered in good faith based on eligibility confirmation, and (d) if the payer applied a retroactive termination, ask them to provide the date the retro-termination was processed versus the date of service. Most payers have an appeals pathway specifically for retroactive termination disputes.
Check for secondary or alternative coverage before billing the patient

Before sending the patient a bill, check whether any secondary coverage was active on the DOS: COBRA election (patient had 60 days from loss of employer coverage to elect COBRA, which applies retroactively), spouse's employer plan, Medicaid (patient may have enrolled after losing employer coverage), or any other insurance. If secondary coverage exists, bill it first. Medicaid, if applicable, is typically the payer of last resort.
If no coverage and no appeal grounds — bill the patient with proper documentation

If coverage was genuinely lapsed and no appeal or secondary coverage applies, the patient is responsible for the full billed amount (not just the contractual rate — the contract does not apply when the patient has no active coverage). Ensure a signed financial responsibility agreement is on file. For Medicare patients, verify an ABN was issued before the service. Send a clear statement itemizing the services and the reason (insurance was inactive on the DOS).

Appeal Template

CO-27 appeal — retroactive termination dispute

Use when you verified eligibility before the service and the payer subsequently applied a retroactive termination. Replace [bracketed fields] with your specifics.

VIA: Formal Claims Appeal Department

Date: [Date]

Payer: [Payer Name] | Claim Number: [Claim #]

Member ID: [Member ID] | Provider NPI: [NPI]

Date of Service: [DOS] | Denial Code: CO-27

RE: Appeal of CO-27 Denial — Coverage Was Verified Active on Date of Service

We are appealing the denial of the above claim under CO-27 (expenses incurred after coverage terminated). We respectfully submit that coverage was active on the date of service per our eligibility verification, and that the CO-27 denial resulted from a retroactive termination processed after the service was rendered.

On [eligibility verification date], we verified the patient's eligibility through [AVS system / payer portal / phone verification]. The response confirmed active coverage under member ID [member ID], Group [group number], effective through at least [coverage end date shown on eligibility response]. A copy of this eligibility confirmation is enclosed.

The service was rendered on [DOS] in good faith, relying on this eligibility confirmation. We subsequently learned that coverage was retroactively terminated effective [retro-term date per payer] — a date before our service — and that this termination was not processed until [date retro-term was processed], after our eligibility check and after the service was rendered.

We request that this claim be reconsidered and paid at the contracted rate, as the retroactive termination could not have been known at the time of service and the claim was submitted in full compliance with the member's coverage as it appeared on the date of service.

Enclosed: eligibility verification confirmation, claim detail, provider agreement reference (Section [X] — good faith eligibility reliance clause, if applicable).

Sincerely, [Practice Administrator], [Practice Name] | Contact: [Name, Phone]

Prevention

How to prevent CO-27

Verify eligibility at every visit — not just at new patient registration. Coverage status changes continuously. An established patient who was active last month may have lost coverage due to job change, non-payment of premiums, or annual enrollment lapses. Run eligibility on every date of service, ideally within 24–48 hours of the appointment.
Save your eligibility verification responses with timestamps. If you receive CO-27 and you verified coverage before the service, your timestamped eligibility response is your appeal evidence. Systems that don't retain AVS responses leave you without documentation when you need it most.
For high-cost services, re-verify eligibility the day before and confirm active status. For surgical procedures, infusions, or other high-dollar services, run a secondary eligibility check the day before the appointment. This catches recent terminations before the service, not after.
Ask patients about recent job changes or life events at check-in. "Has anything changed with your insurance since your last visit?" catches patients who are between jobs, recently married, or recently switched plans — situations that commonly precede CO-27.
Know your payer's COBRA notification timeline. When a patient loses employer coverage, they have 60 days to elect COBRA and it applies retroactively to the day coverage ended. If a patient lost coverage and elected COBRA, COBRA applies to all dates after the employer coverage ended — including dates before the COBRA card arrives. Knowing this prevents unnecessary write-offs on CO-27 claims where COBRA was later elected.

Frequently Asked Questions: CO-27

CO-27 means the payer's records show the patient's insurance coverage had ended before the date of service was incurred. The policy was inactive on the DOS — due to employment loss, premium non-payment, voluntary cancellation, or a retroactive termination applied after your eligibility check. Before treating this as a write-off, verify the exact termination date with the payer and compare it to your eligibility verification record. Many CO-27 denials are appealable when the termination was retroactive and you confirmed active coverage before the service.

If coverage was genuinely lapsed on the DOS and no secondary coverage applies, the patient is responsible for the bill. The CO group code means the contractual adjustment cannot be collected, but the base charges can be billed to the patient as self-pay. However, if you verified eligibility before the service and the payer applied a retroactive termination, appeal the denial before billing the patient — the patient may successfully contest the retro-termination with their insurer. For Medicare patients, an ABN must have been issued in advance for the patient to be billed.

A retroactive termination occurs when a payer terminates coverage effective on a past date — often because an employer processed a separation late, the patient failed to pay a premium, or an enrollment error was discovered. The practical effect is that claims for dates after the retroactive termination date are denied with CO-27, even if your eligibility check at the time of service showed active coverage. When the payer applies a retro-termination, they typically deny all claims in the affected period simultaneously. Retroactive termination CO-27 denials are often successfully appealed when you have an eligibility verification on file dated before the service.

CO-22 means the patient has active coverage, but it is with a different payer that should have been billed first as primary — the current payer should be secondary. CO-27 means the patient had no active coverage at all on the DOS — the policy had ended. CO-22 is always fixable by billing the correct primary. CO-27 may require an appeal (if the termination date is wrong), patient billing (if coverage was legitimately lapsed), or checking for secondary coverage (COBRA, Medicaid, spouse's plan).

Yes. When a patient loses employer coverage, they have 60 days to elect COBRA — and COBRA applies retroactively to the day employer coverage ended. This means a patient may receive a CO-27 denial for services rendered after losing employer coverage, then later elect COBRA, making those services covered retroactively. If you receive CO-27 and the patient was recently laid off or separated from employment, ask whether they have elected or plan to elect COBRA before billing them as self-pay. If they elect COBRA later, resubmit the claim to the COBRA-administered plan for the dates in question.

Related Codes

Expenses Incurred After Coverage Terminated