CO-91: Dispensing Fee Adjustment

What Does CO-91 Mean?

With CO (Contractual Obligation), the CARC 91 adjustment for dispensing fee adjustment 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 91 means the payer adjusted the payment based on dispensing fee adjustment. The reimbursement was calculated using the payer's fee schedule, contracted rate, or regulatory payment methodology rather than the billed charge.

Common scenarios that trigger this adjustment include: the pharmacy billed a dispensing fee higher than the contracted or allowable rate per the payer agreement, and the payer adjusted down to the contracted amount; The payer does not recognize a separate dispensing fee for the type of medication or administration method billed, such as certain pre-packaged or unit-dose medications; The payer's reimbursement methodology already includes the dispensing fee in the overall drug payment rate, and billing a separate dispensing fee results in a duplicate charge adjustment. The group code paired with CARC 91 determines who bears the financial responsibility — CO places it on the provider as a contractual obligation, OA indicates a coordination of benefits or other payer adjustment, PR shifts it to the patient.

Common Causes

How to Resolve

1. Review the adjustment against contract terms Compare the CO-91 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 dispensing fee adjustment does not match your contracted rate. Include the signed contract or fee schedule showing the agreed-upon dispensing fee, the specific claim details, and evidence that the billed fee matches the contractual terms.
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-91:

How to Prevent CO-91

• Maintain current dispensing fee rates in the billing system that match payer contract terms
• Review payer contracts regularly for dispensing fee methodology changes
• Implement automated validation that checks dispensing fees against contracted rates before claim submission
• Ensure only one dispensing fee is billed per prescription fill unless the contract allows otherwise
• Train pharmacy billing staff on payer-specific dispensing fee rules and limitations

Also Filed As

The same CARC 91 may appear with different Group Codes:

Related Denial Codes