ICD-10-CM 2027 diagnosis code
A77.4Ehrlichiosis
A77.4 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About A77.4
A77.4 is the ICD-10-CM diagnosis code for ehrlichiosis. It belongs to category A77 (spotted fever [tick-borne rickettsioses]), block A75-A79 (rickettsioses) and chapter 1 (certain infectious and parasitic diseases). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.
Within A77 (spotted fever [tick-borne rickettsioses]), A77.4 is specifically for ehrlichiosis. Related codes cover spotted fever due to Rickettsia rickettsii (A77.0), spotted fever due to Rickettsia conorii (A77.1), spotted fever due to Rickettsia siberica (A77.2), spotted fever due to Rickettsia australis (A77.3), other spotted fevers (A77.8) and spotted fever, unspecified (A77.9).
To report this condition, pick the subcode that matches the documentation: A77.40 (unspecified), A77.41 (chaffeensis [E. chaffeensis]) and A77.49 (ehrlichiosis).
Don't report A77.4 together with the conditions in its Excludes1 note: anaplasmosis [A. phagocytophilum] (A79.82) and rickettsiosis due to Ehrlichia sennetsu (A79.81).
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Specific codes under A77.4
Coding notes
Notes that apply from higher levels
Instructions written at a parent level also apply to A77.4.
Broader instructions also apply from Chapter 1: Certain infectious and parasitic diseases.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about A77.4
Is A77.4 billable?
- No. A77.4 is a header code. Report one of its more specific subcodes instead.