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N186 Remark Code: Non-Availability Statement Required

N186 means the service required a Non-Availability Statement (NAS), a document from a Military Treatment Facility (MTF) confirming it could not provide the care, and none was on file. The remark directs you to contact the nearest MTF for help.

Quick facts

Code
N186 (RARC N186)
Status
Active In use since February 28, 2003.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim was denied for lack of the NAS. If the provider was responsible for obtaining it, the amount is not billable to the patient.
  • PR (Patient Responsibility): In some situations the beneficiary is responsible for obtaining the NAS and may carry the liability, depending on program rules.
Official description
Non-Availability Statement (NAS) required for this service. Contact the nearest Military Treatment Facility (MTF) for assistance.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N186 means

TRICARE, the health program for uniformed service members, retirees, and their families, has historically required beneficiaries living near a Military Treatment Facility to get certain care there first. When the MTF cannot provide the service, it issues a Non-Availability Statement that allows civilian care to be covered. N186 says that statement was required and not found.

The remark tells providers to reach out to the closest MTF, which is where an NAS is issued. It usually explains CARC 197 or CARC 272.

Common causes

  • The patient lives within the MTF’s service area and the service falls into a category that still requires an NAS.
  • The NAS was issued but not entered in the program’s system, so the claim could not be matched.
  • The NAS covered a different date range or a different facility than the claim.
  • Front-desk staff did not recognise the patient as a TRICARE beneficiary subject to the rule.

How to fix it

  1. Confirm the patient’s TRICARE plan and residence, and check current rules to see whether the service requires an NAS.
  2. Contact the nearest MTF, as the remark directs, and ask whether an NAS was issued or can be issued.
  3. If a statement exists, ask the MTF or regional contractor to confirm it is recorded, then request reprocessing or submit a corrected claim.
  4. If the rules do not require an NAS for this service or plan, appeal with an explanation and any contractor guidance you received.

How to prevent it

At registration, flag TRICARE patients and check their plan type and ZIP code against current NAS rules before scheduling inpatient or other affected services. Keep the MTF contact information handy for the facilities your patients most often live near. More prevention tactics are covered in authorization and referral denials.

Codes that may appear with N186

  • CO-197 (Precertification/authorization/notification/pre-treatment absent.): Precertification or authorization was absent; for these services, the NAS functions as a required pre-service document.
  • CO-272 (Coverage/program guidelines were not met.): Program guidelines were not met because the NAS requirement was not satisfied.
  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Information needed to adjudicate the claim, the NAS, is missing.
  • N139 (Alert: Under 32 CFR 199.13, a non-participating provider is not an appropriate appealing party.): A different TRICARE-related alert about who may appeal a decision.
  • CO-242 (Services not provided by network/primary care providers.): Services not provided by network or primary care providers.

N186 FAQ

Which patients does N186 apply to?

It applies to military health system beneficiaries covered by TRICARE, typically those living near a Military Treatment Facility who used a civilian provider for a service the MTF might have offered.

Is an NAS still required for most care?

The NAS requirement has narrowed over time and now applies to a limited set of services and plan types. Check current TRICARE rules or the regional contractor for the service in question.

Can an NAS be issued after the service?

Program rules differ by situation. Contact the MTF and the regional contractor to ask whether a retroactive statement can be considered.