Denial Code CO-175: Out of Network - Not Authorized
What Does Code 175 Mean?
Payment adjusted because the patient was not referred to an in-network provider or the out-of-network service was not authorized.
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?
Out-of-network service without prior authorization or network exception.
How to Resolve It
- 1Request a network exception if no in-network provider was available
- 2Check No Surprises Act protections for emergency/ancillary services
- 3Appeal with documentation of medical necessity for OON care
- 4If emergency, provide evidence of the emergent circumstances
This Denial Is Often Overturned With a Peer-to-Peer Call
When you receive denial code CO-175, 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.
Want the full strategy?
The P2P Playbook covers payer-specific approaches for denial code CO-175 -- plus 15 denial objections with word-for-word responses, what reviewers are actually thinking, and the 60-second prep framework. Written by a medical director who reviewed cases for major payers.
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