CO-27 denial: Coverage had ended
The payer says the patient's coverage had ended before the date of service.
Common causes
- Eligibility was not checked for the date of service
- The patient changed or lost insurance and did not tell the office
- A plan year or enrollment period changed
How to fix it
- Run an eligibility check for the exact date of service
- If the patient had other coverage, bill that payer
- If there was no coverage, follow your financial policy for patient balances
How to prevent it
- Verify eligibility before each visit, not just at the first one
- Ask patients to report any plan change before they arrive
Zenith billers and AR specialists work denials like this inside your practice-management system, and your practice stays the billing provider. See AR follow-up and medical billing.
Educational summary, not billing or legal advice. Payer rules and deadlines vary; always check the payer’s own policy and the remark code on your remittance.