Other rickettsioses (A79) ICD-10-CM
The A79 code range covers other rickettsioses with 8 ICD-10-CM diagnosis codes. 6 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the A79 Range 8 codes · 6 billable
- A79 Other rickettsiosesNon-billable
- A79.0 Trench fever
- A79.1 Rickettsialpox due to Rickettsia akari
- A79.8 Other specified rickettsiosesNon-billable
- A79.81 Rickettsiosis due to Ehrlichia sennetsu
- A79.82 Anaplasmosis [A. phagocytophilum]
- A79.89 Other specified rickettsioses
- A79.9 Rickettsiosis, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the A79 range.
Anaplasma
A genus of gram-negative bacteria whose organisms are obligate parasites of vertebrates. Species are transmitted by arthropod vectors with the host range limited to ruminants. Anaplasma marginale is the most pathogenic species and is the causative agent of severe bovine anaplasmosis.
Anaplasmosis
A disease usually in cattle caused by parasitization of the red blood cells by bacteria of the genus ANAPLASMA.
Bartonella quintana
A species of gram-negative bacteria in which man is the primary host and the human body louse, Pediculus humanus, the principal vector. It is the etiological agent of TRENCH FEVER.
Trench Fever
An intermittent fever characterized by intervals of chills, fever, and splenomegaly each of which may last as long as 40 hours. It is caused by BARTONELLA QUINTANA and transmitted by the human louse.
About the A79 Code Range
The ICD-10 code section A79 covers various types of rickettsial infections that are distinct from more common rickettsioses. These codes are used to classify less frequent rickettsial diseases such as trench fever, rickettsialpox, and other specified or unspecified rickettsial conditions.
This section includes A79.0 for trench fever, a condition historically linked to lice and characterized by recurring fever. The code A79.1 captures rickettsialpox, caused by Rickettsia akari. Other codes like A79.81 and A79.82 identify specific infections such as Sennetsu fever (also known as Neorickettsiosis) and anaplasmosis due to Anaplasma phagocytophilum. The A79.89 category covers various rarer rickettsial infections, including salmon poisoning disease and bartonellosis, while A79.9 is used when the exact rickettsiosis is not specified. These ICD-10 codes help medical coders accurately report these less common bacterial diseases which are often referred to by their synonyms in clinical practice.
Questions About This Page
How many billable codes are in the A79 range?
Of the 8 codes in this range, 6 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the A79 range classify?
The range classifies other rickettsioses. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
