CO P24 denial code

Claim adjustment reason code P24. Often reported as CO P24.

Adjusted under a PPO arrangement

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What P24 means

On a property and casualty claim, payment was adjusted based on a preferred provider organization (PPO) agreement.

This is a property and casualty code, not one a regular health plan uses. Some carriers access PPO networks to price their claims. P24 means the payer applied a PPO rate that it believes covers you.

It is only used with group code CO. The class of contract information on the remittance may identify the arrangement.

Group codes seen with P24

On a remittance, P24 comes after a group code. These are the ones it is most often reported with:

• CO P24 (Contractual Obligation): The provider's side of the ledger. The reduction comes from the payer contract or a rule the provider has to follow, and the patient normally cannot be billed for it.

The payer chooses the group code for each adjustment, so the same reason code can appear with another group code on your remittance. Read the two together. More about group codes.

Common causes

• The provider has a PPO contract that the property and casualty carrier is allowed to use.
• A network leased the provider's rates to the carrier.
• The provider did not know which network was used.

What to do next

1. Identify the PPO network the carrier used to price the claim.
2. Check your contract with that network for rates and permission to apply them to these claims.
3. Dispute the reduction if you have no valid agreement covering the claim.

Related codes

• P25 (reason code) Adjusted under a medical provider network
• P26 (reason code) Adjusted under a voluntary network (VPN)
• P5 (reason code) Paid at payer's usual and customary rate