A77.49
BillableOther ehrlichiosis
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is A77.49 an HCC code?
No. A77.49 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
A77.49 is the ICD-10-CM diagnosis code for other ehrlichiosis. Other ehrlichiosis refers to a tick-borne bacterial infection caused by Ehrlichia species that doesn't fit into the more common types like Ehrlichia chaffeensis or Ehrlichia ewingii. This rare infection can cause fever, headache, and muscle aches similar to other tick-borne illnesses. A77.49 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering rickettsioses (a75-a79).
A77.49 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 the specific Ehrlichia species identified in the documentation, as A77.40 (Ehrlichiosis chaffeensis), A77.41 (Ehrlichiosis ewingii), and A77.49 (other) are distinct codes with different epidemiologic patterns.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A77.49 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the specific Ehrlichia species identified in the documentation, as A77.40 (Ehrlichiosis chaffeensis), A77.41 (Ehrlichiosis ewingii), and A77.49 (other) are distinct codes with different epidemiologic patterns
- •Document the tick exposure history and geographic location when available, as this supports medical necessity and helps differentiate from other tick-borne illnesses like Lyme disease or Rocky Mountain spotted fever