A03.1 Shigellosis due to Shigella flexneri

The ICD-10-CM code for Shigellosis due to Shigella flexneri is A03.1 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

1: Certain infectious and parasitic diseases (A00-B99)

Section

A00-A09: Intestinal infectious diseases (A00-A09)

Category A03

7 codes (6 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to A03.1:

• Flexner's dysentery
• Hiss-Russell dysentery
• Dysentery, dysenteric (catarrhal) (diarrhea) (epidemic) (hemorrhagic) (infectious) (sporadic) (tropical) › Flexner's
• Diarrhea, diarrheal (disease) (infantile) (inflammatory) › Flexner's (ulcerative)
• Dysentery, dysenteric (catarrhal) (diarrhea) (epidemic) (hemorrhagic) (infectious) (sporadic) (tropical) › Hiss-Russell
• Shigellosis › Group B
• Bacillus › Flexner's
• Dysentery, dysenteric (catarrhal) (diarrhea) (epidemic) (hemorrhagic) (infectious) (sporadic) (tropical) › bacillary › Flexner

Inclusion Terms

• Group B shigellosis

U.S. Hospital Utilization

• An estimated 120 U.S. inpatient stays in 2023 included A03.1 among the documented diagnoses.
• 75 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

HIV Infections (TOC entry)

a. Human Immunodeficiency Virus (HIV) Infections .............................................................. 19

Infectious agents causing diseases in other chapters (TOC)

b. Infectious agents as the cause of diseases classified to other chapters ................................. 22

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)