CO-15: Workers Compensation or Property/Casualty Claim

CO (Contractual Obligation)

What is CO-15?

CO-15 is a Contractual Obligation code indicating the service should be billed to a workers compensation or property/casualty carrier instead of the health plan. The payer determined the injury or condition is work-related or accident-related.

Why Does CO-15 Occur?

  1. Diagnosis code indicates a work-related injury (e.g., ICD-10 codes for workplace injuries).
  2. Auto accident or personal injury claim that should be billed to auto/liability insurance.
  3. Payer's records show the patient has a workers comp or auto claim for the date of service.

How to Fix CO-15 Denials

  1. Confirm whether the condition is work-related or accident-related by reviewing the clinical documentation.
  2. If workers comp applies, submit the claim to the WC carrier with the employer information and injury details.
  3. If auto insurance applies, submit to the auto liability carrier.
  4. If the payer is incorrect and the condition is not work/accident-related, appeal with documentation from the treating provider.

CO-15 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-15, check these related codes: CO-16 (claim differs), CO-45 (fee schedule), CO-29 (timely filing).

Common Questions About CO-15

What does CO-15 mean?

CO-15 indicates workers compensation or property/casualty claim. Check the RARC code on the EOB for the specific reason and follow the resolution steps above.

Can I appeal a CO-15 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-15 denials before submission with payer routing verification. 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.