N859 remark code

Remittance advice remark code N859. Remark codes add detail to the reason code on the same claim line.

No Surprises Act applied

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 N859 means

An alert that the federal No Surprises Act was applied to this claim, and payment disputes go through the federal process.

N859 is an informational alert, not a reason for nonpayment. It tells you the payer treated the claim as protected under the No Surprises Act, which limits patient cost sharing and balance billing for certain out-of-network services.

If you disagree with the payment, the federal open negotiation and independent dispute resolution processes are the usual route. These have their own timelines, so act quickly.

Common causes

• Emergency care was given by an out-of-network provider or facility.
• An out-of-network clinician treated the patient at an in-network facility.
• Out-of-network air ambulance services were provided.

What to do next

1. Bill the patient only the PR amount shown on the remittance.
2. Review the payment against your expected rate and decide whether to open negotiation.
3. Track the federal dispute timelines from the date of the remittance.
4. Keep the remittance and any qualifying payment amount details for the dispute file.

Related codes

• N830 (remark code) Balance billing protections apply
• N864 (remark code) No Surprises Act emergency rules apply
• N130 (remark code) Check plan benefits for restrictions