Denial Code CO-15: Authorization Missing/Invalid
What Does Code 15 Mean?
The authorization number is missing, invalid, or does not apply to the billed services or provider.
Group Code CO (Contractual Obligation): The provider has agreed to accept the payer's determination. The patient is generally not responsible for this amount.
Why Does This Happen?
Prior authorization was not obtained before the service was rendered, or the auth number on the claim does not match.
How to Resolve It
- 1Verify the authorization number and resubmit
- 2If auth was obtained, attach the approval letter
- 3If auth was not obtained, request a retro-authorization
- 4Contact the payer's auth department for status
This Denial Is Often Overturned With a Peer-to-Peer Call
When you receive denial code CO-15, the most effective next step is usually a peer-to-peer (P2P) call with the payer's medical director. During this call, you can present your clinical reasoning directly and often get the denial reversed on the spot.
Our free P2P Call Prep Tool generates a structured script based on your specific case, the payer involved, and the denial reason -- so you walk into the call prepared and confident.