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CO-P12 Denial Code: Workers' Comp Fee Schedule Adjustment

CO-P12 means the workers' compensation payer reduced the billed charge to the amount allowed under the jurisdiction's workers' comp fee schedule. It's the workers' comp version of a fee schedule reduction and is usually a normal adjustment, not a denial.

Quick facts

Code
CO-P12 (CARC P12)
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 standard group. The reduction is required by the state fee schedule, and most states bar billing the injured worker for the difference.
Official description
Workers' compensation jurisdictional fee schedule adjustment. Usage: If adjustment is at the Claim Level, the payer must send and the provider should refer to the 835 Class of Contract Code Identification Segment (Loop 2100 Other Claim Related Information REF). 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) if the regulations apply. 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-P12 means

CARC P12 is a workers’ compensation jurisdictional fee schedule adjustment. X12 limits it to workers’ compensation. It replaced deactivated CARC W1.

Most states set a workers’ comp medical fee schedule that caps what providers can be paid for treating injured workers. When your charge is higher than the schedule allows, the payer reduces it to the schedule amount and reports the difference as CO-P12. Think of it as the workers’ comp counterpart to CO-45 in group health.

The usage note tells you where to look for the basis: for a claim-level adjustment, the 835 class of contract code segment (loop 2100 REF); for a line-level adjustment, the healthcare policy identification segment (loop 2110 REF), when the regulations apply.

Example: you bill $250 for a service. The state workers’ comp schedule allows $142 for that code in your region. The payer pays $142 and reports CO-P12 for $108. The injured worker owes nothing.

Common causes

  • Charges above the state fee schedule, which is normal for most practices.
  • Wrong fee schedule year or version applied for the date of service.
  • Wrong geographic region or locality factor.
  • Facility versus professional schedule confusion.
  • Modifiers not recognized, so the payer priced a different service level.

How to check it

  1. Find the state’s workers’ comp fee schedule for the date of service.
  2. Calculate the expected allowance, including locality, modifier, and multiple procedure rules in that schedule.
  3. Compare it to the allowed amount on the remittance.
  4. If it matches, post CO-P12 as a contractual adjustment. Don’t bill the injured worker.
  5. If it’s too low, request reconsideration from the payer or bill review company, then use the state’s fee dispute process if needed, within the state’s deadlines.

How to prevent problems

  • Load each state’s workers’ comp fee schedule into your billing system.
  • Update schedules when states publish new versions.
  • Check workers’ comp bills against the schedule before sending them.
  • Monitor allowances by payer. An ERA Analyzer can compare CO-P12 allowances to expected fee schedule amounts.

Specialty notes

Orthopedic, PT, and occupational medicine practices treat the most injured workers and should keep state fee schedules current for every state they serve.

Remark codes that may appear with CO-P12

  • N600 (Adjusted based on the applicable fee schedule for the region in which the service was rendered.): Adjusted based on the fee schedule for the region where the service was rendered.
  • N606 (The Oregon allowed amount for this procedure is based upon the Workers Compensation Fee Schedule (OAR 436-009).): An example of a state-specific explanation, here Oregon's workers' comp fee schedule.
  • N608 (The fee schedule amount allowed is calculated at 110% of the Medicare Fee Schedule for this region, specialty and type of service.): An example of a schedule set as a percentage of the Medicare fee schedule.
  • CO-W1Deactivated (Workers' compensation jurisdictional fee schedule adjustment.): The deactivated code that CARC P12 replaced.
  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The general fee schedule reduction used by health plans.
  • CO-P23 (Medical Payments Coverage (MPC) or Personal Injury Protection (PIP)): The auto (MPC/PIP) version of a jurisdictional fee schedule adjustment.
  • CO-P29 (Liability Benefits jurisdictional fee schedule adjustment.): The liability coverage version of a jurisdictional fee schedule adjustment.
  • CO-P13 (Payment reduced or denied based on workers' compensation jurisdictional regulations or payment policies, use only if no other code is applicable.): Reduced or denied under other workers' comp regulations or payment policies.

CO-P12 FAQ

Is CO-P12 a denial?

No. It shows the payer priced the service at the state workers' comp fee schedule amount. The line was paid at that allowance.

Can I bill the injured worker for the CO-P12 difference?

Generally no. Most state workers' comp laws prohibit billing injured workers for amounts above the fee schedule on accepted claims.

How do I know if CO-P12 was calculated correctly?

Look up the fee schedule amount for the code, modifiers, and date of service in the state's published schedule, including any geographic or facility adjustments, and compare it to the allowance.

Where does the payer identify the fee schedule used?

At claim level, in the 835 class of contract code segment (loop 2100 REF). At line level, in the healthcare policy identification segment (loop 2110 REF) when the regulations apply.