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N604 Remark Code: NY No-Fault Fee From WC Schedule

N604 means the New York no-fault insurer calculated the base fee using the New York Workers' Compensation Board Schedule of Medical Fees, as required by No-Fault Regulation 68, under Regulation 83 and/or Appendix 17-C of 11 NYCRR.

Quick facts

Code
N604 (RARC N604)
Status
Active In use since July 15, 2013.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The reduction to the no-fault fee schedule amount. New York no-fault rules generally bar billing the patient for charges above the schedule.
Official description
In accordance with New York No-Fault Law, Regulation 68, this base fee was calculated according to the New York Workers' Compensation Board Schedule of Medical Fees, pursuant to Regulation 83 and / or Appendix 17-C of 11 NYCRR.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N604 means

New York’s no-fault auto system doesn’t have its own fee schedule for most medical services. Instead, No-Fault Regulation 68 points to the Workers’ Compensation Board medical fee schedules. N604 tells you the carrier used that approach to set the base fee for your service.

This is a New York-specific property and casualty remark. It typically appears with CARC P23 or CARC 45.

How to check the fee

  1. Identify the WCB fee schedule that applies to your provider type, such as medical, chiropractic, physical therapy, or behavioral health.
  2. Use the correct region and conversion factor for your location and date of service.
  3. Apply the schedule’s ground rules, which govern multiple procedures, modifiers, and visit limits.
  4. Compare with the allowance. Differences usually trace back to region, provider type, or ground rules.

If the amount is wrong

  • Submit a written explanation and your calculation to the carrier.
  • Correct any code, modifier, or location error with a corrected bill.
  • If the carrier doesn’t adjust, New York no-fault disputes can go to arbitration or court. Watch the time limits.

Keeping it straight

New York no-fault billing also has strict deadlines for submitting bills and responding to verification requests. Build them into your workflow. See timely filing denials for general deadline practices.

Codes that may appear with N604

  • CO-P23 (Medical Payments Coverage (MPC) or Personal Injury Protection (PIP)): A PIP or no-fault jurisdictional fee schedule adjustment.
  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge exceeds the fee schedule or maximum allowable amount.
  • N605 (This fee was calculated based upon New York All Patients Refined Diagnosis Related Groups (APR-DRG), pursuant to Regulation 68.): New York no-fault inpatient hospital fees calculated using APR-DRGs.
  • N603 (This fee is calculated according to the New Jersey medical fee schedules for Automobile Personal Injury Protection and Motor Bus Medical Expense…): New Jersey's PIP fee schedule.
  • N577 (Personal Injury Protection (PIP)): Identifies Personal Injury Protection coverage.

N604 FAQ

Why does a no-fault auto claim use a workers' comp fee schedule?

New York's no-fault regulations adopt the Workers' Compensation Board's medical fee schedules as the basis for no-fault payments to most providers.

Which version of the schedule applies?

The one in effect for the date of service, including any ground rules. Confirm the carrier used the same one.

How do I dispute a New York no-fault fee?

Through the carrier's process and, if unresolved, New York's no-fault arbitration or litigation options, which have specific deadlines.