CO-279: Services Not Provided by Preferred Network Providers

What Does CO-279 Mean?

CO-279 means the provider is not in the patient's preferred network tier and the payment difference is a contractual matter between the provider and payer. The provider cannot bill the patient for the difference. This commonly occurs with tiered network plans where providers in lower tiers receive reduced reimbursement.

CARC 279 indicates that the services billed were rendered by a provider who is not part of the patient's preferred or narrow network tier. This is distinct from a simple out-of-network denial — it specifically targets plans with multiple network tiers where the provider may be contracted with the payer but is not in the patient's specific preferred tier.

The financial impact depends on the Group Code. Under CO, the provider absorbs the cost difference because they are not in the preferred tier — this is common with tiered network plans where contracted providers receive different reimbursement levels. Under PR, the patient is responsible because they chose to receive services from a non-preferred provider, and the cost difference or full charge is their obligation.

This code has become more common as payers expand tiered network designs and narrow network products. A provider who was previously in a broad network may find themselves outside a patient's narrow or preferred tier, triggering this denial even though they still have a contract with the payer.

Common Causes

How to Resolve

Verify the provider's network tier status, check for exceptions or authorizations, and either resolve the network classification or bill the patient for out-of-network costs.

1. Verify network tier status Confirm your current tier assignment with the patient's specific plan — you may be contracted but not in the preferred tier.
2. Check for agreements Review whether a single case agreement or prior authorization exists that covers services at the preferred rate.
3. Contact provider relations If you believe you should be classified as preferred, contact the payer with updated credentialing information.
4. Appeal for extenuating circumstances For emergency care or situations where no preferred provider was available, file an appeal with documentation.

How to Prevent CO-279

• Verify your network tier status with each patient's plan before providing services
• Monitor network participation agreements and tier assignments across payers
• Implement eligibility verification that identifies network tier restrictions at check-in
• Obtain prior authorization or single case agreements when services may fall outside the preferred tier

General Prevention

• Verify the provider's network tier status with each patient's specific plan before providing services
• Stay current on network participation agreements and tier assignments
• Implement electronic eligibility verification that identifies network tier restrictions
• Obtain prior authorization or single case agreements when services may fall outside the preferred network
• Review payer contracts regularly to understand network tier implications

Also Filed As

The same CARC 279 may appear with different Group Codes:

Related Denial Codes