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N801 Remark Code: Tribal Health Plan, 42 CFR 136 Rates

N801 means the services were furnished at a Medicare-participating hospital or critical access hospital (CAH) and paid under a self-insured tribal group health plan in line with federal rules in 42 CFR Part 136. It explains the basis of payment, which is often lower than the facility's billed charges.

Quick facts

Code
N801 (RARC N801)
Status
Active In use since March 1, 2018.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The difference between the billed charge and the amount paid under the federal rule is generally a provider write-off, not a patient balance.
Official description
Services performed in a Medicare participating or CAH facility under a self-insured tribal Group Health Plan, in accordance with Federal Regulation 42 CFR 136.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N801 means

N801 is an explanation of payment basis rather than a request to fix something. It tells a hospital or critical access hospital that the claim was paid under a self-insured tribal group health plan, and that the federal regulation at 42 CFR Part 136 governed how it was paid.

Part 136 covers Indian Health Service programs. Among other things, it limits what Medicare-participating hospitals may receive for services that Indian health programs purchase or refer, often called Medicare-like rates. When a tribal self-insured plan pays a claim under these rules, payment is calculated using a Medicare-based method rather than the facility’s charges or a commercial contract, and N801 flags that on the remittance. The CARC alongside it is usually 45.

Because the rules are federal and tied to Medicare participation, the details of which services and plans they apply to can be technical. Treat the regulation and the plan’s pricing explanation as the source of truth.

What to do

  1. Post the payment and the reduction as indicated. The reduction under CO is generally not a patient balance.
  2. Verify the calculation. Compare the payment against the method the plan says it used. Errors can come from the wrong claim type, wrong dates, or missing claim data.
  3. Confirm the patient’s coverage. Make sure the claim was processed under the right plan and that patient responsibility, if any, was reported as PR.
  4. Ask for pricing detail if the payment looks off, and follow the plan’s reconsideration process if you find an error.

Keep in mind

  • Don’t send a balance bill to the patient for an N801 reduction without confirming what the regulation and plan allow.
  • Keep a separate reporting category for tribal plan payments so their pricing isn’t mistaken for underpayment on commercial contracts.
  • Review how CARC and RARC codes work to read the adjustment lines together.

Codes that may appear with N801

  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge exceeded the maximum allowable under the fee arrangement the regulation sets.
  • CO-131 (Claim specific negotiated discount.): Some payers report the reduction as a claim-specific discount instead.
  • N533 (Services performed in an Indian Health Services facility under a self-insured tribal Group Health Plan.): Services performed in an Indian Health Service facility, rather than an outside Medicare-participating facility, under a tribal group health plan.
  • N757 (Adjusted based on the Federal Indian Fees schedule (MLR).): Payment adjusted based on the Federal Indian fee schedule (Medicare-like rates).

N801 FAQ

Can I balance bill the patient for the difference?

Generally no. The federal rules for these arrangements treat the calculated payment as payment in full for the covered services, so the reduction is not a patient balance. Confirm the details with the plan if you're unsure.

Why does a tribal plan pay Medicare-type rates?

Federal regulations in 42 CFR Part 136 set limits on what Medicare-participating hospitals receive for certain services purchased or referred by Indian health programs. Your facility's Medicare participation brings these rules into play.

What should I check on an N801 claim?

Confirm the amount paid matches how the payer says it calculated the rate, and that the patient and plan are correctly identified. If the calculation looks wrong, ask the plan for its pricing detail.