Sexually Transmitted Infections ICD-10-CM codes

Each STI has its own category and the fourth and fifth characters identify the site. Chlamydia of the lower genitourinary tract is A56.00 when the site is not further specified, A56.01 for cystitis or urethritis, A56.02 for vulvovaginitis, and A56.11 for chlamydial pelvic inflammatory disease. A74.9 (chlamydial infection, unspecified) applies only when the documentation does not state a genitourinary site. Gonorrhea follows the same pattern in A54, with A54.00 for lower genitourinary infection, A54.01 for cystitis or urethritis, and A54.9 when no site is documented.

Syphilis is staged: A51 for early syphilis (A51.0 primary genital, A51.3- secondary skin and mucous membranes, A51.5 early latent), A52 for late syphilis including neurosyphilis (A52.1-) and cardiovascular syphilis (A52.0-), and A53.0 for latent syphilis not specified as early or late. A positive serology without a documented stage or symptoms defaults to A53.9. Congenital syphilis is A50 and is coded from the newborn record.

Genital herpes uses A60: A60.00 for urogenital infection with unspecified site, A60.04 for vulvovaginitis, A60.01 for infection of the penis, and A60.1 for perianal skin and rectum. Herpes simplex at non-genital sites is coded to B00. Trichomoniasis is A59.00 for urogenital infection with unspecified site, A59.01 for vulvovaginitis. Anogenital warts are A63.0; B97.7 is added only when HPV is documented as the cause of a condition classified elsewhere, such as cervical dysplasia.

For an asymptomatic patient tested at a routine visit, use Z11.3 (screening for STIs); for a known contact, use Z20.2 (exposure to infections with a predominantly sexual mode of transmission). Once the result is positive, replace the screening or exposure code with the infection code. Pelvic inflammatory disease of unspecified organism is N73.9 and should not be assigned with A54.24 or A56.11 when the organism is known.