A77.2 ICD-10-CM Code: Spotted fever due to Rickettsia siberica
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Rickettsioses (A75-A79)
A77.2
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceSpotted fever due to Rickettsia siberica
This is a tick-borne bacterial infection caused by Rickettsia siberica that causes spotted fever, characterized by fever, rash, and other flu-like symptoms. It is transmitted through infected tick bites, primarily in Siberia and other parts of Asia.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
Official- North Asian tick fever
- Siberian tick typhus
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A77.2 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for A77.2 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A77.2 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A77.2 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A77.2 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A77.2 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 A77.2 an HCC code?
No. A77.2 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
A77.2 is the ICD-10-CM diagnosis code for spotted fever due to rickettsia siberica. This is a tick-borne bacterial infection caused by Rickettsia siberica that causes spotted fever, characterized by fever, rash, and other flu-like symptoms. It is transmitted through infected tick bites, primarily in Siberia and other parts of Asia. A77.2 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering rickettsioses (a75-a79).
A77.2 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 confirms Rickettsia siberica as the causative organism; do not use this code for other spotted fever types (Rocky Mountain spotted fever uses A77.0).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A77.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation confirms Rickettsia siberica as the causative organism; do not use this code for other spotted fever types (Rocky Mountain spotted fever uses A77.0)
- •This is an infectious disease code that may require additional documentation of the tick exposure or geographic location to support medical necessity for payers