A23.9
BillableBrucellosis, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A23.9 an HCC code?
No. A23.9 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
A23.9 is the ICD-10-CM diagnosis code for brucellosis, unspecified. Brucellosis is a bacterial infection transmitted from animals to humans, typically through contact with infected livestock or consumption of unpasteurized dairy products. This code is used when the specific type of brucellosis cannot be determined or is not documented. A23.9 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering certain zoonotic bacterial diseases (a20-a28).
A23.9 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 the type of brucellosis (such as B. abortus, B. melitensis, or B. suis); query the provider if more specific documentation is available.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A23.9 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 the type of brucellosis (such as B. abortus, B. melitensis, or B. suis); query the provider if more specific documentation is available
- •Brucellosis is a reportable disease in most jurisdictions; ensure proper reporting requirements are met in addition to coding