A91 ICD-10-CM Code: Dengue hemorrhagic fever
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Arthropod-borne viral fevers and viral hemorrhagic fevers (A90-A99)
A91
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceDengue 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.
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
OfficialICD-10-CM does not list inclusion terms for A91 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A91 in this effective period.
Related Child Codes
ICD-10-CM does not list child codes under A91 for this display context.
Includes
OfficialICD-10-CM does not list Includes notes for A91 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A91 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A91 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A91 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A91 in this effective period.
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
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.
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
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