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N600 Remark Code: Regional Fee Schedule Adjustment

N600 means the payer adjusted the charge to the applicable fee schedule for the geographic region where the service was rendered. The difference between your charge and that regional amount is the adjustment.

Quick facts

Code
N600 (RARC N600)
Status
Active In use since July 15, 2013.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The amount above the regional fee schedule is a provider write-off, especially where a jurisdictional fee schedule or contract applies.
  • PR (Patient Responsibility): Uncommon for this code. Where it appears, check whether balance billing is permitted before billing the patient.
Official description
Adjusted based on the applicable fee schedule for the region in which the service was rendered.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N600 means

Fee schedules often pay different amounts in different areas to reflect local costs. N600 tells you the payer priced your service using the regional fee schedule that applies where the service was performed, and reduced your charge to that amount.

It is used often by workers’ compensation and auto payers applying state schedules, and it typically appears with CARC 45, P12, or P23.

Common reasons for a surprising allowance

  • The service location on the claim points to a different region than where care was actually given.
  • A practice with several sites reported the main office rather than the site of service.
  • The payer applied the wrong year of the fee schedule.
  • Modifiers that change pricing, such as professional or technical component modifiers, were missing or wrong.

How to check and fix it

  1. Confirm the service facility address in box 32 of the CMS-1500 and the billing address in box 33.
  2. Look up the applicable regional rate in the fee schedule the payer uses for the date of service.
  3. If the allowance matches, post the adjustment.
  4. If it doesn’t, request repricing with your calculation, or submit a corrected claim with resubmission code 7 if the location data was wrong.

How to prevent problems

Keep each practice location set up with its own address so claims carry the correct site of service, and load current regional fee schedules for your major workers’ comp and auto payers so you can check allowances automatically.

Codes that may appear with N600

  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge exceeds the fee schedule or maximum allowable amount.
  • CO-P12 (Workers' compensation jurisdictional fee schedule adjustment.): A workers' compensation jurisdictional fee schedule adjustment.
  • CO-P23 (Medical Payments Coverage (MPC) or Personal Injury Protection (PIP)): A PIP or medical payments fee schedule adjustment.
  • N655 (Payment based on provider's geographic region.): Payment based on the provider's geographic region.
  • N631 (Medical Fee Schedule does not list this code.): The fee schedule doesn't list the code, so a comparable service was used.
  • N442 (Payment based on an alternate fee schedule.): Payment based on an alternate fee schedule.

N600 FAQ

What defines the region?

The fee schedule does. Many use geographic areas similar to Medicare localities, while state workers' compensation schedules may define their own regions. The service location, not the billing address, usually controls.

Is N600 a denial?

No. It explains a pricing reduction on a service that was otherwise accepted.

What if the wrong region was used?

Check that the service facility address on the claim (CMS-1500 box 32) is correct, then ask the payer to reprice with the right region.