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N6 Remark Code: FEHB Payment Limited to Medicare Rate

N6 means a Federal Employees Health Benefits (FEHB) plan limited its payment under federal law (5 U.S.C. 8904(b)) to the amount Medicare would have allowed if the patient were enrolled in Medicare Part A and/or Part B.

Quick facts

Code
N6 (RARC N6)
Status
Active In use since January 1, 2000; last modified February 28, 2003.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The reduction to the Medicare-equivalent amount is treated as the provider's adjustment. Check FEHB plan guidance before billing the patient for any of the difference.
  • PR (Patient Responsibility): Any amount shown under PR is the patient's cost-sharing calculated on the limited allowance, not the full billed charge.
Official description
Under FEHB law (U.S.C. 8904(b)), we cannot pay more for covered care than the amount Medicare would have allowed if the patient were enrolled in Medicare Part A and/or Medicare Part B.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N6 means

Federal law governing the Federal Employees Health Benefits program lets FEHB plans cap what they pay for covered care at the amount Medicare would have allowed, when the patient is eligible for but not enrolled in Medicare Part A and/or Part B. N6 is how an FEHB plan tells you it applied that cap.

The remark usually sits beside CARC 45 (charge exceeds the allowable) or CARC 223 (mandated federal or state law adjustment). It explains where the allowed amount came from; it does not question whether the service was covered.

Common causes

  • The patient is an FEHB annuitant who declined or never enrolled in Medicare Part B, so professional services are priced at Medicare-equivalent rates.
  • The patient lacks Medicare Part A, so an inpatient stay is priced using Medicare-style rules.
  • Your billed charges are well above Medicare’s fee schedule for the service.

What to do

  1. Recognize it as a pricing outcome. N6 is not asking you to correct the claim.
  2. Verify the calculation. Compare the allowance to the Medicare fee schedule or payment amount for the same service, locality, and date. If it looks wrong, contact the plan with your figures.
  3. Handle the balance carefully. Before billing the patient anything above cost-sharing, confirm what the FEHB plan and federal rules allow. Do not assume the full difference is collectible.
  4. Post the adjustment with the right reason so your reporting separates FEHB limits from ordinary contractual write-offs.

How to prevent it

N6 cannot be avoided through claim edits, but you can plan for it. Record Medicare enrollment status for FEHB members at registration, and set expectations with patients who have chosen not to enroll in Part A or Part B. Estimating payment at Medicare rates for these members avoids surprise variances later.

Codes that may appear with N6

  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge exceeded the allowable, and N6 identifies the Medicare-based federal limit as the source of that allowable.
  • CO-223 (Adjustment code for mandated federal, state or local law/regulation that is not already covered by another code and is mandated before a new code…): An adjustment required by federal law, which N6 then specifies as the FEHB pricing provision.
  • N12 (Policy provides coverage supplemental to Medicare.): A Medicare supplemental policy telling you the member is responsible for what Medicare would have paid.
  • N130 (Consult plan benefit documents/guidelines for information about restrictions for this service.): Directs you to plan documents for benefit limits, a more general message than N6.
  • N219 (Payment based on previous payer's allowed amount.): Payment based on a previous payer's allowed amount, a different reason for a capped allowance.

N6 FAQ

Who does N6 apply to?

Generally FEHB members, often retirees of Medicare age, who do not have the relevant Medicare Part A or Part B coverage. The FEHB plan prices certain services as if Medicare applied.

Is N6 a denial?

No. The claim was processed and paid, but at a lower allowance based on Medicare pricing rather than the plan's usual rate.

Can I appeal N6?

The limit itself comes from federal law, so an appeal is unlikely to change it. You can still ask for review if you think the payer calculated the Medicare-equivalent amount incorrectly.