A03.9 ICD-10-CM Code: Shigellosis, unspecified
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Intestinal infectious diseases (A00-A09)
A03.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceShigellosis, unspecified
Shigellosis is a bacterial infection of the intestines caused by Shigella bacteria, resulting in diarrhea, abdominal cramps, and fever. This code is used when the specific type of Shigella bacteria has not been identified or documented.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- Bacillary dysentery NOS
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A03.9 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for A03.9 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A03.9 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A03.9 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A03.9 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A03.9 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is A03.9 an HCC code?
No. A03.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- A03.9
- Description
- Shigellosis, unspecified
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
A03.9 is the ICD-10-CM diagnosis code for shigellosis, unspecified. Shigellosis is a bacterial infection of the intestines caused by Shigella bacteria, resulting in diarrhea, abdominal cramps, and fever. This code is used when the specific type of Shigella bacteria has not been identified or documented. A03.9 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering intestinal infectious diseases (a00-a09).
A03.9 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.
Use this unspecified code only when the medical record does not specify which Shigella species (A03.0-A03.8) caused the infection; always attempt to obtain more specific documentation from the provider.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A03.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this unspecified code only when the medical record does not specify which Shigella species (A03.0-A03.8) caused the infection; always attempt to obtain more specific documentation from the provider
- •Shigellosis is typically a reportable disease to public health authorities, so ensure proper documentation and reporting requirements are met in addition to coding