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CO-P2 Denial Code: Not Work-Related, Not Workers' Comp

CO-P2 means the workers' compensation carrier determined the injury or illness is not work-related, so it isn't responsible for the claim. The bill usually needs to go to the patient's health plan or other coverage, along with the carrier's determination.

Quick facts

Code
CO-P2 (CARC P2)
Status
Active In use since November 1, 2013; last modified July 1, 2017.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The usual group. The workers' comp carrier won't pay; pursue other coverage rather than billing the patient right away.
  • OA (Other Adjustment): Some carriers use OA, since the responsibility moves to another payer.
  • PR (Patient Responsibility): Used when the carrier indicates the patient is responsible. The patient's health plan is typically the next payer to bill.
Official description
Not a work related injury/illness and thus not the liability of the workers' compensation carrier Usage: If adjustment is at the Claim Level, the payer must send and the provider should refer to the 835 Insurance Policy Number Segment (Loop 2100 Other Claim Related Information REF qualifier 'IG') for the jurisdictional regulation. If adjustment is at the Line Level, the payer must send and the provider should refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment information REF). To be used for Workers' Compensation only.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-P2 means

CARC P2 says not a work-related injury or illness and thus not the liability of the workers’ compensation carrier. X12 restricts it to workers’ compensation. It replaced deactivated CARC 191.

A workers’ comp carrier pays only for injuries and illnesses arising out of employment. When it concludes the condition didn’t happen at work, or isn’t connected to the accepted work injury, it denies with P2. The usage note requires the carrier to cite the jurisdictional regulation: at claim level in the 835 insurance policy number segment (loop 2100 REF, qualifier IG), and at line level in the healthcare policy identification segment (loop 2110 REF).

This is the mirror image of OA-19, where a health plan says the injury is work-related. The two codes together can trap a claim between payers, so documentation from each is important.

Common causes

  • Carrier investigation found the injury happened outside work.
  • Condition not related to the accepted work injury, for example treatment of a separate body part.
  • Pre-existing or degenerative condition the carrier attributes to non-work causes.
  • Employer disputes the injury was reported or occurred on the job.
  • Claim filed under workers’ comp by mistake when the patient never reported a work injury.

How to fix it

  1. Obtain the carrier’s written determination and the regulation cited.
  2. Confirm with the patient how the injury happened and whether they’re contesting the decision.
  3. Bill the patient’s health plan or other coverage, attaching the workers’ comp determination.
  4. Update the claim. Correct employment-related indicators (box 10a) when rebilling a health plan.
  5. Track any dispute. If the workers’ comp decision is overturned, rebill the carrier and refund other payers as required.

How to prevent it

  • Collect injury details at intake, including how and where the injury occurred and whether it was reported to the employer.
  • Verify the claim with the carrier before treatment, including the accepted body parts and conditions.
  • Keep health insurance information on file for workers’ comp patients in case the claim is denied.

Specialty notes

Occupational medicine, orthopedic, and PT practices see CO-P2 most, especially when treatment extends to body parts not included in the accepted claim.

Remark codes that may appear with CO-P2

  • N607 (Service provided for non-compensable condition(s).): The service was for a condition found non-compensable.
  • N624 (The associated Workers' Compensation claim has been withdrawn.): The associated workers' comp claim has been withdrawn.
  • CO-191Deactivated (Not a work related injury/illness and thus not the liability of the workers' compensation carrier Note: If adjustment is at the Claim Level, the…): The deactivated code that CARC P2 replaced.
  • OA-19 (This is a work-related injury/illness and thus the liability of the Worker's Compensation Carrier.): The reverse: a health plan says the injury is work-related and belongs with workers' comp.
  • CO-P4 (Workers' Compensation claim adjudicated as non-compensable.): The workers' comp claim was adjudicated non-compensable.
  • PR-P3 (Workers' Compensation case settled.): The workers' comp case settled with patient responsibility under a set-aside or agreement.

CO-P2 FAQ

What should I do after a CO-P2?

Get a copy of the carrier's determination, then bill the patient's health plan or other coverage and include the workers' comp denial so the health plan doesn't deny with its own work-related code.

What if the health plan says it's work-related?

Send the health plan the workers' comp carrier's written determination. Health plans generally accept a carrier's denial as evidence that workers' comp won't pay.

Can the injured worker dispute the determination?

Yes. Workers' compensation determinations can usually be contested through the state's workers' comp system. If the decision is reversed, the carrier may then pay.

Where is the regulation for a P2 adjustment reported?

At claim level, the carrier reports it in the 835 insurance policy number segment (loop 2100 REF, qualifier IG). At line level, it's in the healthcare policy identification segment (loop 2110 REF).