A20.9
BillablePlague, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A20.9 an HCC code?
No. A20.9 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
A20.9 is the ICD-10-CM diagnosis code for plague, unspecified. Plague is a serious bacterial infection caused by Yersinia pestis that can affect the lungs, lymph nodes, or bloodstream. This code is used when the specific type or form of plague has not been determined or documented. A20.9 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).
A20.9 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 clearly indicate whether the plague is bubonic, pneumonic, or septicemic; query the provider for more specific documentation when possible.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A20.9 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 clearly indicate whether the plague is bubonic, pneumonic, or septicemic; query the provider for more specific documentation when possible
- •Plague is a reportable disease in most jurisdictions, so ensure proper public health notification procedures are followed alongside coding