X12 837D Reference

X12 837D NM101 (Entity Identifier Code): Format, Values, and Testing Notes

Jul 28, 2026 · 4 min read

NM101 is the single element that tells your EDI reader whether the NM1 loop it's currently parsing describes the billing dental office, the individual treating dentist, or the subscriber — and dental claims lean on that distinction more heavily than medical claims because group practices bill centrally while individual dentists still need to be identified for each procedure.

Quick answer

NM101 is the first element of the NM1 segment — a two-character code that identifies which party (billing dentist, treating dentist, subscriber, payer, etc.) the rest of that NM1 loop describes.

Valid code values

Billing Provider — the dental office or group practice submitting the claim for payment

Rendering Provider — the individual dentist who actually performed the procedure

Service Location — used when the procedure was performed at a different location than the billing address

Subscriber — the primary insured party

Patient — used when the patient is not the subscriber

Payer — the dental insurance company adjudicating the claim

Example

Synthetic example Generated by Synthibase

NM1*85*2*BRIGHTSMILE FAMILY DENTAL*****XX*1932847561*

Entity code 85 marks this NM1 loop as the billing dental office, with entity type 2 (organization) and the group's NPI in NM109. Synthetic claim data.

Where this trips people up

Small practices sometimes bill under the treating dentist's own NPI as both the billing and rendering provider, while larger group practices need separate 85 and 82 loops for the group and the individual dentist. Test data generated from a single-dentist template and then reused for a group-practice scenario often leaves out the 82 loop entirely, and the claim validates fine but never actually identifies who performed the work.

→

How to Test X12 837D NM1: A Field-by-Field Breakdown

→

What is X12 837P? Complete Format and Field Guide

→

How to Write EDI Test Cases That Actually Catch Go-Live Failures

Generate every NM1 entity role automatically

Synthibase builds synthetic 837D claims with the full set of NM1 loops — billing dentist, treating dentist, subscriber — correctly coded and linked, so you're testing realistic claims instead of guessing at entity codes.

Start free trial →

This page is written independently by Synthibase for testing and informational purposes. It is not an official publication of HL7 International or X12/Washington Publishing Company, and is not a substitute for reviewing the official standard or your trading partner's companion guide. See our Terms of Service for full legal terms.