ICD-10 Code A64 – Unspecified sexually transmitted disease (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A64 – Unspecified sexually transmitted disease
What it is
A64 is used when the record states a sexually transmitted disease, but the specific infection is not identified. It signals an STI diagnosis without enough detail for a more specific code.
Clinical signs
Clinical features vary; refer to documentation. Patients may present with genital symptoms, exposure history, or positive STI testing, but the chart must not name a specific organism or disease.
When to use this code
Use A64 when the provider documents an unspecified sexually transmitted disease and no further detail is available. It is appropriate when the note confirms an STI, but the type, site, or organism is not recorded. If later documentation identifies the infection, you should code the specific condition instead.
Do not use for
Do not use A64 when the record identifies a specific STI, such as syphilis, gonorrhea, chlamydial infection, or herpes. Check documentation if the provider only documents exposure, screening, or a history of infection.
Coding tip
Before assigning A64, look for a more specific STI diagnosis elsewhere in the chart, including lab results and provider assessment.