HIV Infection ICD-10-CM codes

B20 (HIV disease) is assigned once the patient has any HIV-related illness documented by the provider, and from that point on the patient is always coded B20 on every subsequent encounter, even if currently asymptomatic. Z21 (asymptomatic HIV infection status) is for patients documented as HIV positive who have never had an HIV-related condition; never assign Z21 and B20 together. R75 is used only for inconclusive serology without a definitive diagnosis. Confirmation of HIV status requires only provider documentation, not a positive test.

Sequencing follows the reason for the encounter. When a patient is admitted for an HIV-related condition such as Pneumocystis pneumonia (B59) or Kaposi sarcoma (C46.-), B20 is sequenced first and the related condition follows. When the admission is for an unrelated condition, such as a fracture, that condition is principal and B20 is an additional code. Pregnancy is the exception: a code from O98.7- (O98.711 to O98.719 by trimester, O98.72 for childbirth, O98.73 for the puerperium) is sequenced first, then B20 or Z21.

Z11.4 covers screening in an asymptomatic patient with no known exposure, Z20.6 covers known or suspected exposure, and Z71.7 is added when HIV counseling is provided, including counseling given with a screening test. A patient on pre-exposure prophylaxis is reported with Z29.81 (encounter for HIV pre-exposure prophylaxis) rather than Z20.6. Do not assign B20 for a patient described as HIV positive without symptoms or related conditions; that is Z21.

B97.35 (HIV 2 as the cause of diseases classified elsewhere) is rarely appropriate because B20 already covers HIV disease of either type; it is used only when a specific condition is classified elsewhere and the provider attributes it to HIV-2. Terms such as AIDS, ARC, and HIV-related illness all map to B20.