Your staff at the front desk managed to verify the patient’s insurance. You submitted the claim with no issues. Then the EOB came back with a denial code 27. This happens a lot more often than most billing departments would like to admit, and it occurs rapidly when patients change jobs, miss COBRA payments, or change insurance plans and do not inform their doctors about it.
CO 27 denial code is not a difficult coding error. It is primarily a timing issue combined with an issue regarding verification. Once your team learns what triggers the 27-denial code, the vast majority of them won’t occur again.
This guide covers the CO 27 denial code description, the difference between CO-27 and PR-27, common causes, and a detailed path to resolution, including current implications of the 2026 Medicare Advantage market exits for your company’s denial incident volume.
What is Denial Code 27 in Medical Billing?
Denial code 27 is a standardized Claim Adjustment Reason Code (CARC) maintained by the Washington Publishing Company (WPC). Its official description reads:
“Expenses incurred after coverage terminated.”
If a payer denies a claim and includes the Denial Code 27 on the Explanation of Benefits (EOB) or Electronic Remittance Advice (ERA), that means the insurance plan in their possession was no longer active on the Date of Service (DOS). The adjudication engine of the payer didn’t find a valid eligibility segment on file for the member ID submitted, the date of service, and the plan details, so the claim was denied.
When CO 27 denial code appears with the RARC N619 (coverage terminated for non-payment of premium), the cause of the denial is due to a premium lapse; therefore, the resolution to the claim for payment will be wholly different than that for a claim denied due to a billing error.
What Does ‘Coverage Terminated’ Mean in Claims?
Coverage terminated means the patient’s insurance policy was no longer active when the service was delivered. In practical billing terms, this surfaces in four distinct scenarios.
Policy lapse due to non-payment
Coverage loss from a policy lapse due to non-payment is the most common reason. Many insurance companies allow for a grace period; therefore, termination will be retroactive to the last date the account was paid. Patients may present valid-looking cards with an active status; however, the payer has already closed the eligibility segment.
Employment-based coverage loss
Losing coverage due to employment change, lay-off, or reduction of hours will terminate any employer-sponsored insurance on the day the last premium was paid. If the individual does not make their COBRA payment by midnight of the pay period immediately following the payment, it will terminate retroactively after the grace period has expired.
Common Reasons for CO 27 Denial Code
No Insurance Verification at the Time of Service
The CO 27 denial code will be one of the most frequent and preventable denial codes that providers encounter. If active coverage is not confirmed at both the time the appointment is scheduled and again when the individual arrives, inactive or terminated policies can go undetected until the claim is submitted to the insurance company as an inactive payer. At both touch points, active eligibility verification must be done, not only at the time of registration.
Outdated Insurance Information on File
Changes in coverage can occur due to many circumstances, such as patients changing insurance plans or losing coverage through their employer without notifying their provider. Billing an old insurance plan after coverage termination generates a 27 denial code on every claim until the record is corrected with updated payer information and a new member ID.
Incorrect Data Entry
Inaccurate data entries for subscriber ID, date of birth, and/or patient name can prevent the insurance company’s ability to match the file to an active eligibility segment, resulting in a CO 27 denial code regardless of whether or not the subscriber is active. An incorrect digit entered in the subscriber ID will result in the claim receiving a CO 27 denial code.
Coordination of Benefits (COB) Sequencing Errors
When a patient carries primary and secondary insurance, there can often be some confusion. When the medical bill is generated in the name of the wrong payer, a denial that looks like coverage termination is created, but this is actually a COB sequencing issue. Confirm the correct primary payer at every encounter, particularly for Medicare patients who also carry commercial coverage.
Patient Plan Switch Without Notification
Patients who switch insurance plans during open enrollment or following a qualifying life event frequently forget to inform their provider. This results in an ongoing attempt to bill the terminated plan versus the new active coverage, which generated the CO027 denial code that would have been completely avoided if the provider had asked a single question during the intake process.
Patients newly acquiring insurance policies through yearly open enrollment or a qualifying life event often fail to notify their provider of the switch,
What is the PR-27 Denial Code?
The PR-27 denial code carries the same official description as CO-27 — “expenses incurred after coverage terminated” — but the Claim Adjustment Group Code determines who bears financial responsibility, and that changes everything about how you act on it.
In the PR-27 denial code, the payer has decided that the financial responsibility (liability) for the claim lies with the patient, not the provider. Therefore, under a PR-27 denial code, the Provider can bill the patient directly for the amount denied. This is the primary distinction between a CO-27 denial code, where the provider has a contractual obligation written off the CO-27 and cannot bill the patient for the denied amount.
PR-27 most commonly appears when the patient’s plan places coverage maintenance responsibility on the member, and that coverage lapses. Before converting any PR-27 denial code to a patient balance, verify the termination was legitimate and not a payer-side data error. A wrongly issued PR-27 is just as appealable as a CO-27.
Difference Between CO-27 and PR-27 Denial Code
| CO-27 | PR-27 | |
| Group Code | Contractual Obligation | Patient Responsibility |
| Financial Liability | Provider | Patient |
| Can bill the patient? | No | Yes |
| Common cause | Payer contract or admin error | Patient’s own coverage lapsed |
| Appeal path | Appeal with eligibility proof | Verify termination; bill patient or appeal |
| Write-off risk | Provider absorbs if not overturned | Patient balance; collection risk |
Preventive Strategies for Denial Code CO 27
Automate eligibility checks at every touchpoint:
Run real-time electronic eligibility verification 24 hours before each appointment and again at check-in.Also run any termination dates in the future flagged by the payer’s portal, and send an automatic alert to your staff so they can address this prior to the patient arriving.
Build a hard-stop protocol for Medicare Advantage patients:
Establish a hard stop for Medicare Advantage patients. Beginning in 2026, no MA card should be accepted at face value unless there has been a newly verified eligibility inquiry completed prior to accepting the card or treating the MA patient, regardless of the patient’s history at your practice. The 2026 carrier exits make this an absolute requirement.
Correct demographic data at registration:
Correct demographic information upon registration or verification should include: subscriber ID, date of birth, and the spelling of the name, which should be verified against the insurance card at every visit. A single transposed digit can create a CO 27 denial code; this is costly in time consumed by your staff resolving the denial code.
Train staff on COBRA grace period rules:
Educate your staff on COBRA grace period rules. Frequently, patients will assume they still have active COBRA coverage when, in actuality, one missed premium resulted in an automatic shutdown of their COBRA coverage retroactive to the last date a premium was paid. The front desk staff should ask specific questions about prior COBRA status during the insurance verification; assuming continuity of COBRA coverage could put your practice in a bind.
Run monthly denial trend audits:
If 27 denial code occurrences are clustering around a specific payer, plan type, or patient demographic, that pattern points to a systemic eligibility verification gap. Identifying those patterns early is the foundation of effective denial management.
How to Resolve Denial Code 27 (CO-27 & PR-27)
Step 1: Verify eligibility for the exact date of service
Pull the payer’s eligibility verification portal or call provider services and confirm the exact coverage termination date for the DOS on the denied claim. Your only source for this confirmation should not solely be the denial notification, as the payor’s system may have provided a retroactive termination, which is different than what was discovered during check-in. If CO-27 is billed with RARC N619, this identifies that insurance has been retroactively terminated due to a premium lapse, which leads you to your next action!
Step 2: Check for data entry errors
Check for any errors entered during data entry. Review the claim for any subscriber ID, birth date, age error, misspelling of name, & DOS error. If there is a demographic mismatch, that is an all-too-common reason for CO-27 denials on otherwise active insurance plans. If there was a data entry issue found, then correct it & resubmit the claim as a corrected claim (Claim Frequency Code 7) using EDI 837 format.
Step 3: Update insurance records and locate active coverage
To verify their current insurance status, reach out to each patient. If the patient has a new coverage plan, it is important to get the updated member ID, company, and effective date, and submit an updated claim to the new active payer. This protects against future issues with patients having previously used outdated UHC cards and now having coverage through a completely different plan due to the 2026 exit of Medicare Advantage Plans.
Step 4: Appeal with proof of eligibility
As long as your records reflect that the insurance was active and eligible to bill for the date of service (DOS) with an eligibility verification screenshot from a payer’s website, a copy of the confirmation from the payer’s web portal, or a reference number from an eligibility verification telephone call, then file a formal appeal to the provider. CMS 2026 regulations prohibit backdated terminations of Medicare Advantage plans for retroactively terminated services once prior authorization is already in place.
Representation for retroactively terminated services with respect to prior authorization will not be allowed under the 2026 regulations. All information regarding eligibility for coverage must be included with your claim during the timely filing period allowed by your payer.
Step 5: Convert to patient responsibility or discuss alternatives
If the provider’s claim is denied as not being active and already verified as terminated by virtue of having a denial code for that termination, then the claim will fall under PR-27. This means that the patient will need to be responsible for the bill since the claim no longer has any value to the provider. Prior to issuing a patient statement on any PR-27 claim, verify whether the termination was legitimate and validate that there was no error on the payer’s side.
You can also explore other payment arrangements, such as a payment plan, financial assistance, or a charity eligibility program, with patients who may have lost their enrollment due to unforeseen job loss or a lapse in continuation of coverage under COBRA. Although the PR-27 and CO-27 denial codes have identical descriptions as per the official CARC description of “Expenses incurred after coverage terminated”, the liability for the amount billed ultimately resides with the patient.
How CO 27 Denial Code Affects Revenue Cycle
Recurring 27 denial code occurrences are not just a claims problem. They are a front-end workflow problem that compounds across every stage of the revenue cycle. Every unresolved CO-27 increases your Accounts Receivable (AR) Days and complicates patient relationships with unexpected balance bills.
In addition to creating a strain on patient relationships, denial codes divert billing staff from efforts to recover money in a higher-value environment. Each reworked denied claim costs between $25 & $118 in administrative expense according to MGMA, and most individuals do not ever rework a denied claim for Covered Services Post-Coverage Termination.
Conclusion
Expenses incurred after coverage terminated represent one of the top reasons insurance claims get denied across every specialty and payer type. The repeated occurrence of denial code 27 should prompt an audit of your front-end eligibility verification process, as opposed to viewing each claim as an isolated billing issue when the same denial code appears for multiple patients/payers.
If denials for coverage termination are taking more staff time than your practice can reasonably maintain, Nexus io has denial management services that include eligibility verification in real-time, denial tracking by payer, and denial appeal services provided in a complete revenue cycle workflow, so claims for terminated coverage will be identified before submitting to the payer, not after.
