X12 837I Reference

X12 837I SBR01 (Payer Responsibility Sequence Number Code): Format, Values, and Testing Notes

Jul 28, 2026 · 4 min read

One character decides whether a payer thinks it's being billed first or second on an inpatient stay, and inpatient claims involving Medicare plus a supplemental plan hit this far more often than a routine office visit ever does.

Quick answer

SBR01 is the Payer Responsibility Sequence Number Code on an X12 837I claim — a single-letter code that establishes whether the SBR loop it appears in represents the primary, secondary, or tertiary payer for that institutional claim.

Valid code values

Primary — the payer responsible for adjudicating the claim first

Secondary — the payer responsible after the primary has adjudicated, common on Medicare-plus-supplemental inpatient claims

Tertiary — a third payer, seen on more complex coordination-of-benefits stays

Example

Synthetic example Generated by Synthibase

SBR*P*18*GRP-55210*MEDICARE PART A*****MA*

SBR01 = P marks Medicare as the primary payer for this synthetic inpatient claim. Synthetic claim data.

Where this trips people up

On a claim with a Medicare primary and a Medicaid or supplemental secondary payer, it's common for test fixtures to build the primary loop correctly and then clone it for the secondary payer without updating SBR01 from P to S. The file validates syntactically since both letters are legal values, but the secondary payer sees itself listed as primary and either rejects the claim outright or adjudicates it as if no other coverage exists, which produces a benefits calculation that's wrong in a way that's hard to trace back to a single character.

→

X12 837I SBR Segment Guide: Fields, Format, and Testing Gotchas

→

How to Test 837I Institutional Claims: A Complete Guide

→

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

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Synthibase generates synthetic 837I claims with SBR01 correctly sequenced across Medicare, Medicaid, and commercial payer loops — no PHI, no sequence mistakes.

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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.