A03.1
BillableShigellosis due to Shigella flexneri
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A03.1 an HCC code?
No. A03.1 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
A03.1 is the ICD-10-CM diagnosis code for shigellosis due to shigella flexneri. A bacterial infection of the intestines caused by Shigella flexneri bacteria, which spreads through contaminated food or water and causes severe diarrhea, abdominal cramps, and fever. This is a contagious disease that primarily affects the digestive system. A03.1 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering intestinal infectious diseases (a00-a09).
A03.1 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Verify the specific Shigella species (flexneri) is documented in the medical record before assigning this code, as different species have different codes (A03.0, A03.1, A03.2, A03.3, A03.9).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A03.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the specific Shigella species (flexneri) is documented in the medical record before assigning this code, as different species have different codes (A03.0, A03.1, A03.2, A03.3, A03.9)
- •Document any complications such as dehydration, electrolyte imbalances, or systemic manifestations separately, as these may require additional codes