Denial codes · Denial code
CO-27 on a nutrition claim: coverage had ended by the date of service
By Javier Alvarez · Updated · 4 min read
| Official description | Expenses incurred after coverage terminated. |
|---|---|
| Group code | Usually CO on the remit; the balance becomes a patient matter only once no coverage applies |
| Related codes | CO-26 (before coverage began), N30, N52 |
| Most common cause | New job or new plan year, old card still on file |
| Can be reversed | COBRA elected late, or premiums paid within a grace period |
| Fix route | New claim to the current payer; reprocessing if reinstated |
CO-27 is the denial that usually arrives in February. The patient changed jobs, or the employer switched carriers at the new plan year, and nobody updated the card on file. The visit was fine, the claim was fine, it just went to a plan that no longer covered the patient. The fix is to find where the coverage went.
What CO-27 means (official X12 wording)
The X12 Claim Adjustment Reason Code list defines CARC 27 as:
"Expenses incurred after coverage terminated."
Its mirror image is CARC 26, "Expenses incurred prior to coverage," which you get when the visit happened before a new plan's effective date. Both are eligibility denials: the payer is only saying the member was not covered on that date.
Remark codes that often travel with it include N30, "Patient ineligible for this service," and, for managed care plans, N52, "Patient not enrolled in the billing provider's managed care plan on the date of service."
The usual causes on nutrition claims
1. A new plan the practice never heard about
Nutrition care is a series of visits. A patient who started MNT in the fall and is still coming in January may have a new card that never made it to you. Most CO-27s are this: the claim belongs to a different payer.
2. Retroactive termination
You checked eligibility, it was active, and the claim still came back CO-27. Coverage can be ended retroactively when an employer reports a termination late or when premiums were not paid. An eligibility response is only as current as the payer's file on the day you checked.
3. The Marketplace grace period
People who buy coverage on the ACA Marketplace with advance premium tax credits get a three-month grace period when they stop paying premiums. Under 45 CFR 156.270(d), the plan must pay appropriate claims for the first month but "may pend claims for services rendered to the enrollee in the second and third months of the grace period." If the premiums are never paid, coverage ends and those pended claims can be denied, often as CO-27. Plans must notify providers that claims in the second and third months may be denied. (Other plans may have their own grace periods; check the plan's terms.)
4. COBRA not yet elected
After a job loss, a person usually has a window to elect COBRA continuation coverage, and once elected and paid it generally applies back to the day the old coverage ended. A claim for a visit in that window can be denied CO-27 and later become payable.
5. Medicaid or managed-care changes
Medicaid eligibility and managed care plan assignment can change month to month. A patient can move from one Medicaid managed care plan to another, or back to fee-for-service. The claim goes to whoever was responsible on the date of service.
How to fix a CO-27
- Confirm the dates. Check the termination date in the payer's portal or by phone. Is the visit really after it? A data-entry error in the date of service on your claim also produces CO-27 (and that one you fix with a corrected claim, frequency code 7).
- Ask the patient for current coverage. New employer plan, spouse's plan, Marketplace plan, Medicare, Medicaid. Run an eligibility check on the new plan for the date of service.
- Bill the new payer with a new claim. A corrected claim goes to the payer that processed the original; for a different payer you send a new original claim. The new payer's timely filing clock started on the date of service, so move quickly.
- If coverage is being reinstated (COBRA elected, grace-period premiums paid, an employer error corrected), ask the patient to confirm with the plan, then call the plan and ask it to reprocess the claim. Note the reference number of the call.
- If there was no coverage, the visit is self-pay. Bill the patient under your financial policy, at your self-pay rate if you have one, and explain why in plain words.
How to prevent CO-27
- Re-verify coverage at every visit in January and at the first visit after any job, marriage or move the patient mentions.
- Check eligibility for the date of service, not just "today," when you bill a backlog.
- Ask one question at every check-in: "Any change to your insurance since last time?"
- Have a signed financial policy that says the patient is responsible if coverage is not active. It makes a CO-27 self-pay conversation much easier.
- Keep your verification script handy. Our insurance verification call script recommends re-verifying every plan year and ideally monthly for active clients; electronic eligibility checks explains what a 271 response does and does not tell you.
If the payer cannot find the patient at all, rather than finding an ended policy, the code is usually CO-31. For every other code, see the denial code lookup.