OA P2 denial code

Claim adjustment reason code P2. Often reported as OA P2 or CO P2.

Not a work related injury or illness

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 P2 means

The workers' compensation carrier says the condition is not work related, so it is not liable for the claim.

Only workers' compensation payers use this code. The carrier has decided the injury or illness did not arise from employment, which ends its liability for the treatment billed.

The rule behind the decision may be referenced on the remittance. In practice, the patient's own health plan may become the payer to bill next, depending on the plan's rules for work related exclusions.

Group codes seen with P2

On a remittance, P2 comes after a group code. These are the ones it is most often reported with:

• OA P2 (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.
• CO P2 (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 employer or carrier disputes that the injury happened at work.
• The treated condition is not the one accepted on the workers' compensation claim.
• The carrier finished its review and denied compensability of the condition.

What to do next

1. Confirm the claim decision and claim number with the workers' compensation adjuster.
2. Ask the patient for health insurance information and bill that plan with the carrier's denial attached.
3. Check whether the patient is contesting the decision before final billing.
4. Keep the carrier's denial in the account in case the decision is reversed.

Related codes

• P4 (reason code) Workers' comp claim found non-compensable
• P3 (reason code) Workers' comp settled: patient responsible
• 109 (reason code) Not covered by this payer, send elsewhere