CO P5 denial code

Claim adjustment reason code P5. Often reported as CO P5 or OA P5.

Paid at payer's usual and customary rate

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 P5 means

With no state fee schedule to apply, this property and casualty carrier set the price itself using its customary fee data.

It belongs to property and casualty billing, such as workers' compensation or auto medical claims. P5 explains the pricing method: the carrier used its own market data to set the amount because nothing in law capped it.

The reduction is a pricing decision, so the question is whether the payer's amount is reasonable compared with what the market pays.

Group codes seen with P5

On a remittance, P5 comes after a group code. These are the ones it is most often reported with:

• CO P5 (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.
• OA P5 (Other Adjustment): Used for adjustments that are neither the provider's contractual write-off nor the patient's share. It often appears with coordination of benefits, for example when another payer already paid.

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 state has no fee schedule for this type of claim or service.
• The payer's reasonable and customary amount is lower than the billed charge.
• No network or contract rate applied to the claim.

What to do next

1. Check whether a fee schedule or network contract should have applied to the claim.
2. Compare the payment with typical rates for the service in your area.
3. Request reconsideration with market data if the payment seems unreasonably low.
4. Check the payer's policy and state rules before billing the patient for any difference.

Related codes

• P12 (reason code) Workers' comp fee schedule adjustment
• P24 (reason code) Adjusted under a PPO arrangement
• 45 (reason code) Charge exceeds the allowed amount