CO-111Contractual ObligationContractual
CO-111 Denial Code: Not covered unless provider accepts assignment
The service is only payable when the provider accepts assignment — billed non-assigned, it denies.
Why CO-111 happens
- ●Non-assigned claim for a service the payer mandates assignment on (e.g., Medicare drugs, clinical lab)
How to fix a CO-111 denial
- 1
Rebill as assigned; payment then flows to the practice at the allowed rate
How to prevent it
Know the mandatory-assignment service list for Medicare and your major payers.
Drowning in CO-111 denials?
OakClaim works every denial within 48 hours and builds prevention rules so they stop recurring.