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N859 Remark Code: Federal No Surprises Act Applied

N859 is an alert that the Federal No Surprises Act was applied when this claim was processed. It also tells you the payment amount can be disputed through the federal process, which starts with open negotiation and can proceed to independent dispute resolution (IDR).

Quick facts

Code
N859 (RARC N859)
Status
Active In use since November 1, 2021; last modified March 1, 2022.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • PR (Patient Responsibility): Patient cost sharing is limited to the in-network-based amount the Act allows. That's all the patient owes.
  • CO (Contractual Obligation): The difference between the charge and the payment can't be balance billed to the patient under the Act.
Official description
Alert: The Federal No Surprise Billing Act was applied to the processing of this claim. Payment amounts are eligible for dispute pursuant to any Federal documented appeal/ grievance/ dispute resolution process(es).
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N859 means

The No Surprises Act protects patients from surprise out-of-network bills for emergency care, certain nonemergency care at in-network facilities, and air ambulance services. It also sets up a payment dispute system between out-of-network providers and plans. N859 is the general alert that the Act governed this claim.

Two practical messages come with it. The patient’s share is limited to what the plan reported as PR, and if you disagree with the payment, the federal dispute process is the way to challenge it, not balance billing.

What to do

  1. Limit patient billing to the PR amount and refund anything collected above it.
  2. Decide quickly whether to dispute. The open negotiation clock generally starts when you receive the initial payment or notice of denial.
  3. Send an open negotiation notice to the plan if you want a higher payment, and keep records of the exchange.
  4. Consider federal IDR if negotiation fails, weighing fees and the likely outcome.
  5. Track NSA claims separately so their deadlines don’t get lost in normal appeal queues. See how CARC and RARC codes work for reading the full remittance.

Codes that may appear with N859

  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge was reduced to the amount paid under the Act.
  • PR-2 (Coinsurance Amount): Coinsurance calculated under the Act's cost-sharing rules.
  • N858 (Alert: State regulations relating to an Out of Network Medical Emergency Care Act were applied to the processing of this claim.): A state out-of-network emergency care law was applied instead.
  • N877 (Alert: This initial payment is provided in accordance with the No Surprises Act.): Marks an initial payment under the Act and notes open negotiation is available.
  • N874 (Alert: This final payment was determined through open negotiation, in accordance with the No Surprises Act.): The final payment was reached through open negotiation.

N859 FAQ

How do I dispute an N859 payment?

Start federal open negotiation by sending the plan a notice within 30 business days of the initial payment or denial. If negotiation doesn't resolve it within 30 business days, either party may start federal IDR within a short window afterward.

Can I bill the patient the balance?

No. For services protected by the Act, you may collect only the patient cost sharing the plan reported.

Does N859 mean the payment is final?

Not necessarily. It shows the Act was applied. Other remarks on the claim, such as N877 or N874, indicate whether the payment is initial or final.