Reference·NM1 Segment·NM101
X12 837P Reference

Testing X12 837P NM101: What Entity Identifier Code Actually Needs to Handle

Jul 27, 2026 · 4 min read
NM102 →

NM101 is the single element that tells your EDI reader which of the dozen-plus NM1 loops in an 837P claim it's currently parsing. Miss it, and a perfectly well-formed name segment gets attached to the wrong role entirely.

Quick answer

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

Valid code values

85
Billing Provider — the entity submitting the claim for payment
87
Pay-to Provider — used only when payment goes to a different address than the billing provider
82
Rendering Provider — the individual who actually performed the service
DN
Referring Provider — the provider who referred the patient
DK
Ordering Provider — the provider who ordered a service or supply
IL
Subscriber — the primary insured party
QC
Patient — used when the patient is not the subscriber
PR
Payer — the insurance company adjudicating the claim

Example

Synthetic example Generated by Synthibase
NM1*85*2*RIVERBEND FAMILY MEDICINE*****XX*1932847561*

Entity code 85 marks this NM1 loop as the billing provider, with entity type 2 (organization) and an NPI in NM109. Synthetic claim data.

Where this trips people up

Test files generated by hand or by a legacy mapper sometimes reuse entity code 85 for a group practice and its rendering physician, when the claim actually needs 85 for the billing entity and a separate 82 loop for the individual provider. The claim validates fine but the payer can't tell who actually performed the service, and it comes back as a provider-identification denial instead of a syntax error.

How to Test X12 837P NM1: A Field-by-Field Breakdown
What is X12 837P? Complete Format and Field Guide
How to Validate X12 EDI Files Before Payer Submission
Generate every NM1 entity role automatically
Synthibase builds synthetic 837P claims with the full set of NM1 loops — billing, rendering, referring, subscriber — correctly coded and linked, so you're testing realistic claims instead of guessing at entity codes.
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