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N866 Remark Code: NSA Air Ambulance Protections Apply

N866 is an alert that the claim is subject to the No Surprises Act provisions for services furnished by nonparticipating air ambulance providers. The patient's cost sharing is limited to in-network levels, and the air ambulance provider can't balance bill the patient for the rest.

Quick facts

Code
N866 (RARC N866)
Status
Active In use since March 1, 2022.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • PR (Patient Responsibility): Patient cost sharing is calculated at in-network levels under the Act.
  • CO (Contractual Obligation): The difference between the charge and the plan's payment can't be billed to the patient.
Official description
Alert: This claim is subject to the No Surprises Act provisions that apply to services furnished by nonparticipating providers of air ambulance services.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N866 means

Air ambulance transports are often out of network and expensive, which made them a major source of surprise bills. The No Surprises Act includes a specific provision for them. N866 tells you the plan applied it: the patient pays only in-network cost sharing, and the air ambulance provider can’t bill them for the rest.

The alert is aimed mainly at air ambulance billers. Ground ambulance claims fall outside the Act’s balance billing protections.

What to do

  1. Bill the patient only the PR amount and stop collections on any remaining balance.
  2. Review the payment and the plan’s QPA disclosure.
  3. Start open negotiation within the deadline if you think the payment is too low, and prepare for IDR if talks fail.
  4. Report required air ambulance data where federal rules require it, and keep claim documentation complete in case of dispute.

Codes that may appear with N866

  • CO-45 (Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.): The charge was reduced to the plan's payment for the air transport.
  • PR-2 (Coinsurance Amount): Coinsurance at in-network levels.
  • N864 (Alert: This claim is subject to the No Surprises Act provisions that apply to emergency services.): The Act's provisions for emergency services.
  • N862 (Alert: Member cost share is in compliance with the No Surprises Act, and is calculated using the lesser of the QPA or billed charge.): Cost share calculated from the lesser of the QPA or the billed charge.

N866 FAQ

Does the No Surprises Act cover ground ambulance?

No. The Act's balance billing protections cover air ambulance services, not ground ambulance. Some states have their own ground ambulance protections.

How is the patient's share calculated?

For air ambulance services, cost sharing is generally based on the lesser of the QPA or the billed charge, and it counts toward the patient's in-network deductible and out-of-pocket maximum.

How do I dispute the payment?

Through federal open negotiation and, if needed, IDR. Air ambulance providers use the same federal process as other out-of-network providers, with some air ambulance-specific factors.