Are HIV-infected injection drug users taking HIV tests?

Knowledge of infection is essential for human immunodeficiency virus-type 1 (HIV-1) treatment initiation and epidemic control. This study evaluates infection knowledge among infected injection drug users and acceptance of confidential testing among injection drug users, particularly those infected with HIV-1.

A total of 810 injection drug users entering treatment in Contra Costa County, Calif, were examined. Clients were tested with unlinked (blinded) tests and simultaneously counseled and offered voluntary confidential HIV-1 antibody testing. Data on confidential testing acceptance, previous testing, drug use, and demographic information were collected.

Of the 810 tested, 105 (13.0%) were infected. The current confidential test was accepted by 507 (62.6%). HIV seroprevalence in the unlinked survey was four times greater than in the voluntary survey (13% and 3.5%, respectively). HIV-1 infection was associated with refusal of a confidential test largely because most infected injection drug users (n = 58; 55.2%) already knew of their infection. Of the 47 injection drug users who were not aware of their infection, 12 (25.5%) accepted the test. Although African-American injection drug users presented with a higher infection rate (37.3%), they were three times less likely to know of their infection.

"In-clinic" HIV-1 testing is highly accepted, and most infected clients in treatment will learn their status. Nevertheless, voluntary testing data are likely to yield considerable underestimates of the true rate of infection among injection drug users.