CO-56: Procedure/Treatment Not Proven Effective

What Does CO-56 Mean?

With CO (Contractual Obligation), the CARC 56 denial for procedure/treatment not proven effective is the provider's contractual responsibility. The patient is not liable for this amount. However, the provider may appeal with supporting clinical or administrative documentation if the denial is believed to be in error.

CARC 56 indicates procedure/treatment not proven effective. The payer determined that the service or a portion of it does not meet coverage criteria under the patient's current plan benefits or the applicable coverage rules.

Common scenarios that trigger this adjustment include: the payer's medical review determined the treatment has not been proven effective for the patient's condition; Available clinical studies do not demonstrate effectiveness to the payer's standards; Payer requires use of proven alternatives before covering this treatment. The group code paired with CARC 56 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 denial Examine the CO-56 denial and any RARC codes to understand the specific basis for the coverage determination.
2. Gather supporting documentation Collect medical records, clinical notes, authorization documents, or other evidence that supports the medical necessity or coverage of the denied service.
3. File the appeal Appeal with peer-reviewed studies, clinical guidelines, and outcomes data demonstrating the treatment's effectiveness for the patient's specific condition. Include a physician letter explaining why this treatment was selected over alternatives.
4. Track the appeal outcome Monitor the appeal status and follow up as needed. If denied again, consider further levels of appeal if available.

Common RARC Pairings

The RARC code tells you exactly what triggered the CO-56:

How to Prevent CO-56

• Check payer policies on treatment coverage before performing
• Obtain prior authorization for treatments that may be questioned
• Document clinical rationale for treatment selection
• Provide evidence-based justification with the claim

Also Filed As

The same CARC 56 may appear with different Group Codes:

Related Denial Codes