N350 remark code

Remittance advice remark code N350. Remark codes add detail to the reason code on the same claim line.

Unlisted code needs a description

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 N350 means

A service billed with an unlisted or not otherwise classified code needs a description, and it was missing or unclear.

Unlisted and not otherwise classified codes do not say what was done, so payers require a short description on the claim and sometimes supporting records. N350 means that description was absent or not good enough to price the service.

It explains a missing information reason code, often 16, and the claim can usually be corrected.

Common causes

• The claim note or description field was blank for an unlisted procedure code.
• The description was too vague to identify the service or drug.
• A drug billed with a not otherwise classified code lacked the drug name, dose or NDC.

What to do next

1. Add a clear description of the service, or drug name and dose, in the claim note field.
2. Attach the operative note or invoice if the payer asks for it.
3. Submit a corrected claim with the description included.
4. Check whether a specific code now exists that should be used instead.

Related codes

• N850 (remark code) Service narrative missing or invalid
• N706 (remark code) Documentation missing
• 16 (reason code) Missing information or billing error