A78
BillableQ fever
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A78 an HCC code?
No. A78 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
A78 is the ICD-10-CM diagnosis code for q fever. Q fever is a contagious infection caused by bacteria that spreads through contact with infected animals or contaminated materials, causing flu-like symptoms such as fever, chills, and fatigue. It can affect the lungs, heart, and other organs if left untreated. A78 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering rickettsioses (a75-a79).
A78 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.
Q fever is a reportable disease in most jurisdictions; verify local reporting requirements when assigning this code.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A78 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Q fever is a reportable disease in most jurisdictions; verify local reporting requirements when assigning this code
- •Distinguish between acute Q fever (A78) and chronic Q fever (B90.9 or other chronic manifestations) as they have different treatment approaches and clinical outcomes