CO-155: Patient Refused the Service/Procedure

What Does CO-155 Mean?

With CO (Contractual Obligation), the CARC 155 adjustment for patient refused the service/procedure is a contractual reduction. The provider absorbs this amount per the payer contract or regulatory payment methodology. The patient is not responsible for the adjusted amount. Review the remittance to confirm the adjustment is consistent with your contract terms.

CARC 155 appears on a remittance when the payer applies an adjustment for patient refused the service/procedure. Review the group code and any accompanying RARC codes to understand the full context of this adjustment.

Common scenarios that trigger this adjustment include: the patient explicitly refused to receive the service or procedure that was ordered, and the payer denies the claim because the service was not actually rendered; The provider incorrectly billed for a service that the patient refused, and the claim was denied because the service should not have been submitted; The patient withdrew consent during the procedure, and the full service as billed was not completed. The group code paired with CARC 155 determines who bears the financial responsibility — CO places it on the provider as a contractual obligation, PR shifts it to the patient, OA indicates a coordination of benefits or other payer adjustment.

Common Causes

How to Resolve

1. Review the adjustment against contract terms Compare the CO-155 adjustment with your payer contract to confirm the reduction is consistent with agreed terms or regulatory methodology.
2. Verify the adjustment amount Confirm the dollar amount of the adjustment is calculated correctly based on the contracted rate and the service provided.
3. Appeal if the adjustment is incorrect Appeal only if the service was actually provided with patient consent. Include signed consent forms, clinical documentation showing the service was rendered, and a letter explaining that the patient did not refuse the service.
4. Process the contractual adjustment If the adjustment is correct per contract terms, process it accordingly in your billing system. This amount cannot be transferred to the patient.

Common RARC Pairings

The RARC code tells you exactly what triggered the CO-155:

How to Prevent CO-155

• Ensure patients fully understand the importance and benefits of recommended services before scheduling
• Document patient refusals clearly in the medical record with a signed refusal form
• Do not submit claims for services that patients have refused
• Educate patients about potential risks of refusing recommended services and address their concerns
• Implement pre-visit communication to confirm the patient's willingness to proceed with planned services
• Train billing staff to verify that services were actually rendered before submitting claims

Also Filed As

The same CARC 155 may appear with different Group Codes:

Related Denial Codes