CO-27: Services billed after coverage termination

The payer is telling you that some or all of the services were provided after the member's policy ended. From their view, there was no active coverage in force on the dates you billed, so the plan has no financial responsibility for those dates. Mechanically, the payer eligibility edits compare the claim service dates to plan enrollment and termination records. Any service date after the termination date is denied under CO-27 and moves to provider write-off unless you correct coverage, dates, or route the claim to the correct payer.

In behavioral health, CO-27 hits hard on longer stays where coverage changes mid-episode, like residential, detox, or PHP. Example: a 28-day residential SUD stay where the member's commercial plan terminates on day 10, but billing sends a single UB-04 per diem claim for all 28 days to the old plan. Days 11 to 28 are denied as CO-27 and you lose over half the stay if you do not rebill the new payer. It also shows up with Medicaid and MCOs when eligibility flips month to month. A PHP or IOP episode that crosses months can deny after a retro termination or MCO reassignment, especially when the behavioral benefit is carved out to a different administrator and your team keeps billing the prior plan. Telehealth and outpatient mental health claims are not immune. A therapist might keep seeing a patient weekly, but the patient's employer plan term date is the end of the month. If the front desk does not re-verify and update coverage, you will see CO-27 on every 90837 or 95-modifier telehealth visit after the term date, and by the time you catch it, timely filing to the new payer may be at risk.

• Verify eligibility for all denied dates of service and confirm the exact termination date with the payer or portal.
• Check if the patient had other coverage in effect for those dates, including Medicaid, an MCO switch, or a new commercial plan.
• If part of a stay is before termination, split the claim so covered days go to the terminated plan and the rest to the active plan.
• Correct billing errors such as wrong date span, wrong payer, or missing coordination of benefits, then submit a corrected claim to the appropriate payer.
• If there is truly no coverage, follow your financial policy for converting to self-pay, and do not bill the patient for amounts contractually prohibited.
• Appeal only when you have proof the payer's termination date is wrong or coverage was active, and include eligibility screenshots or payer letters.

• Re-verify eligibility at admission, again at the start of each month, and whenever a stay crosses a benefit period.
• Build billing edits that flag claims where any covered day is after the payer's recorded termination date before submission.
• Ensure utilization review and billing teams share daily or weekly census lists with eligibility status for longer levels of care like residential, detox, PHP, and IOP.
• Train front-desk and scheduling staff to confirm coverage changes at each visit for outpatient and telehealth, including new ID cards and plan switches.