Reference·SBR Segment·SBR01
X12 837P Reference

What Is X12 837P SBR01? Payer Responsibility Sequence Number Code, Explained for Testers

Jul 27, 2026 · 4 min read
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Two SBR loops both marked P on the same claim isn't a syntax error, so a translator will pass it straight through — the payer is the one who catches it, usually by rejecting the claim outright instead of coordinating benefits.

Quick answer

SBR01 is the Payer Responsibility Sequence Number Code in an X12 837P claim — a single-character code stating whether the payer named in this SBR loop is responsible as the primary, secondary, or tertiary payer.

Valid code values

P
Primary — this payer is billed first and pays before any other coverage applies
S
Secondary — this payer pays after the primary payer has adjudicated
T
Tertiary — this payer pays after both primary and secondary have adjudicated

Example

Synthetic example Generated by Synthibase 
SBR*P*18*GRP-9042217*ACME REGIONAL HEALTH PLAN*****CI*

The P immediately after SBR is SBR01, marking this loop as the primary payer for the claim. Synthetic claim data.

Where this trips people up

Building a secondary-payer loop by duplicating the primary loop and forgetting to change SBR01 from P to S is one of the most common causes of COB claims that adjudicate incorrectly — the claim structurally has two loops, but the payer sequencing logic that's supposed to distinguish them never actually fires.

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X12 837P SBR Segment Guide: Fields, Format, and Testing Gotchas
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COB Claims Testing: How to Generate Coordination of Benefits Scenarios
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What is X12 837P? Complete Format and Field Guide
Test primary, secondary, and tertiary sequencing correctly
Synthibase generates synthetic 837P claims with SBR01 sequenced correctly across every payer loop, so coordination-of-benefits logic gets exercised the way it will in production.
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