ICD-10 Code A59 – Trichomoniasis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A59 – Trichomoniasis
What it is
A59 identifies trichomoniasis, a sexually transmitted infection caused by Trichomonas vaginalis. Use it when the record documents this parasitic infection without a more specific site or complication.
Clinical signs
Clinical features vary; refer to documentation. Commonly noted findings include vaginal discharge, irritation, dysuria, or urethral symptoms, but you should code only when the diagnosis is documented.
When to use this code
Use A59 when the clinician confirms trichomoniasis in the assessment, problem list, or discharge summary. It also fits follow-up encounters when the infection remains active or is still being managed. If the note specifies a more detailed subcategory, code that instead.
Do not use for
Do not use A59 for nonspecific vaginitis, urethritis, or other sexually transmitted infections unless trichomoniasis is documented. Check documentation if the organism is not named or the condition is only suspected.
Coding tip
Code the confirmed diagnosis only, and look for site or complication details that may require a more specific ICD-10-CM code.