N386 remark code

Remittance advice remark code N386. Remark codes add detail to the reason code on the same claim line.

Decision based on an NCD

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What N386 means

The determination came from a National Coverage Determination, a Medicare coverage policy that applies nationwide.

Medicare issues National Coverage Determinations for some services, setting which patients and conditions qualify. N386 tells you this claim was judged against one, and the decision does not vary by region.

It adds detail to the reason code on the claim, often 50 or 167. The NCD and any related coding instructions usually show which diagnosis or condition was needed.

Common causes

• The diagnosis billed is not one the NCD covers.
• The service exceeded a frequency limit set in the NCD.
• Conditions the NCD requires, such as prior testing or specific findings, were not documented.

What to do next

1. Look up the NCD in the Medicare Coverage Database and review its coverage conditions.
2. Check the record for a covered diagnosis that was not coded.
3. Correct the claim if coding was the issue, or appeal with records if the criteria were met.
4. Check whether an advance notice was signed before shifting any balance to the patient.

Related codes

• N115 (remark code) Decision based on an LCD
• 50 (reason code) Not medically necessary per the payer
• N569 (remark code) Not covered for the diagnosis