Does ICD-10 code B96.21 confirm a diagnosis?

No. A code helps standardize documentation and claims, but it should not be read as a substitute for a clinician's full assessment.

ICD10BillableValid for clinical use

ICD-10 Code B96.21: Shiga toxin-producing Escherichia coli [E. coli] [STEC] O157 as the cause of diseases classified elsewhere

Name: ICD-10 Code B96.21: Shiga toxin-producing Escherichia coli [E. coli] [STEC] O157 as the cause of diseases classified elsewhere
Creator: HealthAssure Clinical Team
Published: 2026-05-21T06:01:41.013Z

B96.21 is a billable ICD-10 diagnosis code used to classify Shiga toxin-producing Escherichia coli [E. coli] [STEC] O157 as the cause of diseases classified elsewhere in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Certain infectious and parasitic diseases (A00-B99).

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Certain infectious and parasitic diseases (A00-B99).

When is it used?

May be used when a clinician documents shiga toxin-producing escherichia coli [e. coli] [stec] o157 as the cause of diseases classified elsewhere in a patient's medical record.
May appear in hospital records, claims, referrals, and clinical documentation.
This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

A code alone does not explain severity, treatment plan, or outcome.
A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter

1Certain infectious and parasitic diseases (A00-B99)

block

B95-B97Bacterial and viral infectious agents

Official coding notes

Inclusion terms

E. coli O157:H- (nonmotile) with confirmation of Shiga toxin
E. coli O157 with confirmation of Shiga toxin when H antigen is unknown, or is not H7
O157:H7 Escherichia coli [E. coli] with or without confirmation of Shiga toxin-production
Shiga toxin-producing Escherichia coli [E. coli] O157:H7 with or without confirmation of Shiga toxin-production
STEC O157:H7 with or without confirmation of Shiga toxin-production

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

Infectious Disease SpecialistGeneral Physician

Sibling codes

B96.20Unspecified Escherichia coli [E. coli] as the cause of diseases classified elsewherebillable B96.22Other specified Shiga toxin-producing Escherichia coli [E. coli] [STEC] as the cause of diseases classified elsewherebillable B96.23Unspecified Shiga toxin-producing Escherichia coli [E. coli] [STEC] as the cause of diseases classified elsewherebillable B96.29Other Escherichia coli [E. coli] as the cause of diseases classified elsewherebillable

Coding guidelines

Common synonyms

Shiga toxin-producing Escherichia coli [E. coli] [STEC] O157 as the cause of diseases classified elsewhere

Frequently asked questions

Code details

CodeB96.21

SystemICD10

Display nameShiga toxin-producing Escherichia coli [E. coli] [STEC] O157 as the cause of diseases classified elsewhere

ChapterCertain infectious and parasitic diseases (A00-B99)

BlockBacterial and viral infectious agents

Flags

BillableYes

Valid clinical useYes

Source

SourceICD-10

Version2026-annual

Releaseannual

Year2026

Index terms

Matched terms

Escherichia coli(E. coli), as cause of disease classified elsewhereEscherichia coli(E. coli), as cause of disease classified elsewhereEscherichia coli(E. coli), as cause of disease classified elsewhereEscherichia coli(E. coli), as cause of disease classified elsewhere

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.