CO-27: Expenses Incurred After Coverage Terminated

CO (Contractual Obligation)

What is CO-27?

CO-27 is a Contractual Obligation code indicating the service was rendered after the patient's coverage end date. The patient's insurance had already terminated when the service was provided.

Why Does CO-27 Occur?

  1. Patient's coverage was terminated before the date of service due to non-payment, job change, or plan cancellation.
  2. COBRA coverage lapsed and was not renewed.
  3. Patient's employer terminated group coverage but the termination was not yet reflected in the payer's system.

How to Fix CO-27 Denials

  1. Verify the patient's coverage termination date on the payer portal.
  2. If the patient has new coverage, submit the claim to the new payer.
  3. If no coverage exists, bill the patient directly as self-pay.
  4. If the termination date is incorrect in the payer's system, appeal with proof of active coverage (e.g., premium payment receipts, employer confirmation).

CO-27 by Payer

Payer Common RARC Appeal Deadline Notes
UnitedHealthcare Varies 60 days from remittance Reconsideration required before formal appeal.
Anthem Varies 365 days from denial notice Check state-specific provider manual for variations.
Aetna Varies 180 days from denial Strict in-network filing enforcement.
Cigna Varies 180 days from denial Cigna COB team: 1-800-244-6224.
Medicare Varies 120 days (redetermination at MAC) Five levels of appeal starting with MAC redetermination.

Related CARC Codes

If you are seeing CO-27, check these related codes: CO-44 (subscriber not eligible), CO-27 (coverage terminated), CO-26 (prior to coverage).

Common Questions About CO-27

What does CO-27 mean?

CO-27 indicates expenses incurred after coverage terminated. Check the RARC code on the EOB for the specific reason and follow the resolution steps above.

Can I appeal a CO-27 denial?

Yes. Commercial payers allow 60-365 days to appeal depending on the payer. Gather supporting documentation before filing. Medicare allows 120 days for a redetermination request.

Altair catches CO-27 denials before submission with real-time eligibility checking. See how pre-submit claim scoring works.

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This reference is for informational purposes. Always verify against current payer policies and CMS guidelines. Last updated: 2026-03-09.