CO-27: expenses incurred after coverage terminated.

What X12 says CARC 27 means

Expenses incurred after coverage terminated.

CARC 27 · Start 01/01/1995.

In plain terms: The service date falls after the patient's coverage ended under this plan.

What it means on a remittance

The payer compares the date of service with the term date on its eligibility file. If the service date is later, it reports CARC 27. Its sibling, CARC 26, covers expenses incurred before coverage began. Retired CARC 28 (“coverage not in effect at the time the service was provided”) was marked redundant to codes 26 and 27.

Typical causes

• The patient's coverage ended (job change, plan change, aging off a dependent plan, non-payment of premium).
• Eligibility was checked on an earlier date and not on the date of service.
• The payer's file shows a retroactive termination processed after the visit.
• The patient has a new plan that the claim did not name.

These are common billing patterns, not a diagnosis of your claim. The remittance and the payer's policy decide.

What to check

1. Run an eligibility check for the date of service and note the term date.
2. Ask the patient whether there is a new plan, a second plan, or a continuation of coverage.
3. Check the claim for the right payer name and member ID for that date.
4. Note the filing deadline for any other payer you now have to bill.

Correct, resubmit or appeal

If the term date is right, bill the patient's new or other payer, or follow your policy for patient balances if no coverage applies. If the payer's term date is wrong, send proof of coverage for the date of service and ask for reprocessing. For Medicare the filing limit is one calendar year after the date of service (42 CFR 424.44), and a redetermination request is due 120 days from receipt of the notice. Other payers set their own limits.

Medicare dates that apply

Medicare claims must be filed no later than the close of the period ending 1 calendar year after the date of service (42 CFR 424.44(a)(1)), with exceptions in 424.44(b). A redetermination request must be filed within 120 calendar days from the date a party receives the notice, receipt is presumed 5 days after the notice date (42 CFR 405.942(a)), and a late request can be considered for good cause (405.942(b)). Clerical errors, including inaccurate data entry, are handled by the contractor as reopenings instead of redeterminations (42 CFR 405.980(a)(3)). The tool above runs the date math.

Related codes

X12 does not publish a table that pairs each CARC with remark codes; the payer picks the remark code and prints it beside the CARC on the same remittance line. These X12 remark codes carry wording that speaks to this reason, so look for them:

• N30 — Patient ineligible for this service.
• N382 — Missing/incomplete/invalid patient identifier.

Other codes: CARC 109 (claim belongs with another payer), CARC 29 (filing deadline expired). The full lookup reads any code on this page.

Worked example (hypothetical)

A patient's employer plan ended on June 30. A visit on July 12 denies CO-27. The front desk learns the patient started a new plan on July 1, rebills that plan, and records the new member ID.

Sources

• X12: Claim Adjustment Reason Codes — code text, usage notes and dates (list dated 10/30/2026, retrieved 2026-11-02)
• X12: Remittance Advice Remark Codes — remark code text (retrieved 2026-11-02)
• 42 CFR 424.44, 42 CFR 405.942 and 42 CFR 405.980 — eCFR, current through 2026-10-29 (retrieved 2026-11-02)

Code descriptions are X12 copyrighted material, quoted here only for the codes on this page and linked to the owner. For the full lists, use X12. Every rule above was read from these pages on November 2, 2026. Payers revise code lists, contracts and policies, so confirm anything that affects a claim or a deadline with the payer.