Repeat negative human immunodeficiency virus (HIV) testing in San Francisco: magnitude and characteristics.

The authors assessed the characteristics of repeat human immunodeficiency virus (HIV) testers at publicly funded sites in San Francisco. During 1992-1993, 31% of all HIV tests were performed on persons testing negative for the third time or more. Persons with greater numbers of prior negative tests were less likely to test HIV-positive. Repeat negative testers were more likely than first-time negative testers to be homosexual or bisexual males, homosexual or bisexual injection drug users (IDUs), or heterosexual IDUs. Repeat testers who seroconverted were more likely to be in these same transmission categories than repeat testers who remained negative. Because of the similarities in risk profile between those most likely to retest and those most likely to seroconvert, attempts to limit repeat testing must proceed cautiously.