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N599 Remark Code: Florida No-Fault Reasonable Amount

N599 means the auto insurer paid a 'reasonable amount' under the policy and the Florida No-Fault Statute, and set that amount at 200% of the participating Medicare Part B fee schedule for the locale where the service was provided.

Quick facts

Code
N599 (RARC N599)
Status
Active In use since July 15, 2013.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The reduction to the Florida no-fault reasonable amount. Whether the patient can be billed for the difference depends on Florida law and the policy.
  • PR (Patient Responsibility): Any patient share, such as a PIP deductible or coinsurance, is reported separately under PR.
Official description
Our payment for this service is based upon a reasonable amount pursuant to both the terms and conditions of the policy of insurance under which the subject claim is being made as well as the Florida No-Fault Statute, which permits, when determining a reasonable charge for a service, an insurer to consider usual and customary charges and payments accepted by the provider, reimbursement levels in the community and various federal and state fee schedules applicable to automobile and other insurance coverages, and other information relevant to the reasonableness of the reimbursement for the service. The payment for this service is based upon 200% of the Participating Level of Medicare Part B fee schedule for the locale in which the services were rendered.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N599 means

Florida’s no-fault law lets auto insurers limit what they pay for PIP medical care to a reasonable amount, and allows a fee-schedule method based on Medicare. N599 tells you the insurer used that method: the allowance for this line is 200% of the participating-provider Medicare Part B fee schedule for the locale where you provided the service.

This is a state-specific property and casualty code. It generally appears with CARC P23, P22, or 45.

How to check the allowance

  1. Find the Medicare Part B participating amount for the service, locale, and applicable year.
  2. Double it and compare it to the allowed amount on the remittance.
  3. Account for modifiers and multiple-procedure rules that also affect the Medicare amount.
  4. Look for the PIP share. The payment is usually less than the allowance because of the policy’s coinsurance and any deductible.

When to dispute

  • The allowance is lower than 200% of the correct Medicare amount.
  • The carrier used the wrong locale or fee schedule year.
  • The service has no Medicare amount, and a different rule under the statute should apply.

Send a written request to the carrier with your calculation and follow Florida’s pre-suit and dispute procedures, which have their own notice requirements. Many providers work with counsel on contested PIP payments.

How to stay ahead

Load a Florida PIP rate table built from the Medicare schedule so each payment can be checked on posting. An ERA analysis that compares allowed amounts to expected rates will flag underpayments across carriers.

Codes that may appear with N599

  • CO-P23 (Medical Payments Coverage (MPC) or Personal Injury Protection (PIP)): A PIP jurisdictional fee schedule adjustment.
  • CO-P22 (Payment adjusted based on the Medical Payments Coverage (MPC) and/or Personal Injury Protection (PIP)): Adjusted under PIP jurisdictional regulations or payment policy.
  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge exceeds the fee schedule or maximum allowable amount.
  • N577 (Personal Injury Protection (PIP)): Identifies Personal Injury Protection coverage.
  • N603 (This fee is calculated according to the New Jersey medical fee schedules for Automobile Personal Injury Protection and Motor Bus Medical Expense…): The New Jersey PIP fee schedule, a different state's method.
  • N608 (The fee schedule amount allowed is calculated at 110% of the Medicare Fee Schedule for this region, specialty and type of service.): An allowance at 110% of the Medicare fee schedule under Act 6.

N599 FAQ

Does N599 apply outside Florida?

No. It refers specifically to the Florida No-Fault Statute and is used on Florida auto claims.

Which Medicare fee schedule year applies?

Florida's statute and the policy language control this. Confirm with the carrier which year and locale it used before disputing the math.

Is 200% of Medicare the payment or the allowed amount?

N599 describes how the reasonable amount was set. PIP then pays its share of that amount, and any deductible or coinsurance appears separately on the remittance.