Infections with a predominantly sexual mode of transmission (A50-A64) ICD-10-CM
The A50–A64 section covers infections with a predominantly sexual mode of transmission with 169 ICD-10-CM diagnosis codes, of which 142 are billable in fiscal year 2026. The section is organized into the 13 code ranges listed below.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
- human immunodeficiency virus [HIV] disease B20
Code Ranges in This Section 13 ranges · 169 codes
The info icon previews the code ranges inside each row and its instructional notations from the official Tabular List.
About the A50–A64 Code Range
ICD-10 codes A50-A64 are used to classify infections that are primarily spread through sexual contact. These codes cover a range of sexually transmitted infections including syphilis, gonorrhea, chlamydial infections, chancroid, granuloma inguinale, trichomoniasis, and herpesviral infections.
This code range uniquely identifies both early and late stages of syphilis (A50-A53), covering congenital syphilis with its diverse manifestations like syphilitic oculopathy and neurosyphilis, and acquired forms with cardiovascular and neurological complications. The range also includes gonococcal infections (A54) affecting various sites such as the genitourinary tract, eyes, musculoskeletal system, and central nervous system, with terms like “gonorrhea” and “gonococcal arthritis” linked to specific codes for clarity. Chlamydial infections (A55-A56) including lymphogranuloma venereum are detailed with codes for genital and extragenital presentations. Codes for chancroid (A57), granuloma inguinale (A58), trichomoniasis (A59), and anogenital herpes (A60) capture infections with characteristic lesions and viral causes. The range concludes with A63 and A64 covering other sexually transmitted diseases like anogenital warts caused by human papillomavirus and unspecified sexually transmitted infections, helping coders accurately assign diagnoses when precise identification is unavailable.
Questions About This Page
How many codes are in the A50-A64 range?
The A50-A64 range contains 169 ICD-10-CM diagnosis codes in FY 2026. 142 of them are billable, and the rest are category headers that organize the section.
What conditions does A50-A64 cover?
The range covers infections with a predominantly sexual mode of transmission. The code ranges listed above break it into groups of related conditions, and each one links to its own page with the full code list.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
