CO-25: Code Edit: Procedure Code Mismatch

CO (Contractual Obligation)

What is CO-25?

CO-25 is a Contractual Obligation code indicating a code edit found the procedure code does not match expected patterns. This is similar to CO-4 but specifically addresses code edits rather than NCCI bundling. The payer's editing system flagged an inconsistency in the code combination.

Why Does CO-25 Occur?

  1. Procedure code and modifier combination fails the payer's code edit logic.
  2. Add-on code billed without the required primary procedure code.
  3. Code pair flagged by the payer's proprietary editing system (beyond NCCI).
  4. Mutually exclusive codes billed on the same date of service.

How to Fix CO-25 Denials

  1. Identify which code pair or combination triggered the edit by reviewing the RARC code.
  2. If an add-on code was billed without the primary, add the primary procedure code.
  3. If the edit is a payer-specific rule (not NCCI), check the payer's code editing manual.
  4. Appeal if the code combination is clinically appropriate and the payer's edit is incorrect.

CO-25 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-25, check these related codes: CO-4 (incompatible coding), CO-97 (bundled service), CO-16 (claim differs).

Common Questions About CO-25

What does CO-25 mean?

CO-25 indicates code edit: procedure code mismatch. Check the RARC code on the EOB for the specific reason and follow the resolution steps above.

Can I appeal a CO-25 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-25 denials before submission with code edit checking. See how pre-submit claim scoring works.

← Back to CARC Code Reference Hub
This reference is for informational purposes. Always verify against current payer policies and CMS guidelines. Last updated: 2026-03-09.