ICD-10-CM 2027 diagnosis code

A23Brucellosis

Not billable — use a more specific code

A23 is a header code, so it can't be reported by itself. Choose one of the 6 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 A23

A23 is the ICD-10-CM diagnosis code for brucellosis. It belongs to block A20-A28 (certain zoonotic bacterial diseases) and chapter 1 (certain infectious and parasitic diseases). It is a header code, so it can't be reported by itself; one of its 6 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: A23.0 (due to Brucella melitensis), A23.1 (due to Brucella abortus), A23.2 (due to Brucella suis), A23.3 (due to Brucella canis), A23.8 (brucellosis) and A23.9 (unspecified).

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 A23

Coding notes

IncludesFurther defines the content of the category

Malta fever
Mediterranean fever
undulant fever

Notes that apply from higher levels

Instructions written at a parent level also apply to A23.

Broader instructions also apply from Chapter 1: Certain infectious and parasitic diseases.

Codes whose notes reference A23

M49Code first

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 A23

Is A23 billable?: No. A23 is a header code. Report one of its more specific subcodes instead.