A91
BillableDengue hemorrhagic fever
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A91 an HCC code?
No. A91 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
A91 is the ICD-10-CM diagnosis code for dengue hemorrhagic fever. Dengue hemorrhagic fever is a severe form of dengue infection transmitted by mosquitoes, characterized by bleeding, low platelet counts, and potentially life-threatening complications. It occurs when a person is infected with dengue virus a second time, typically with a different strain than their initial infection. A91 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering arthropod-borne viral fevers and viral hemorrhagic fevers (a90-a99).
A91 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 documentation clearly states 'dengue hemorrhagic fever' or 'DHF' to distinguish from uncomplicated dengue fever (A90), as hemorrhagic manifestations are required for this code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A91 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation clearly states 'dengue hemorrhagic fever' or 'DHF' to distinguish from uncomplicated dengue fever (A90), as hemorrhagic manifestations are required for this code
- •This code includes dengue shock syndrome; do not assign additional codes for shock unless the documentation specifies a different type of shock unrelated to the dengue infection