Performance of serological assays for early detection of human immunodeficiency virus type 1 seroconversion

Early detection of sexually transmitted human immunodeficiency virus type 1 (HIV-1) infection was investigated in newly infected persons to determine the sensitivities of currently available serologic techniques. Serial serum samples were obtained from 51 newly infected persons in a cohort of 1,153 homosexual or bisexual men participating in the Baltimore Center of the Multi-Center AIDS Cohort Study during the first 2.5 years of follow-up. Of 51 participants, 45 seroconverted between any two seminannual visits and 6 were found to have been infected just prior to study entry. Five enzyme-linked immunosorbent assays (ELISAs), two immunoblots, and an HIV-1 P24 antigen capture assay were performed on a panel of all serial serum samples from these individuals. The sensitivity of ELISAs varied between 50 and 84% in seroconverters with less-developed antibody response. In this group of seroconverters, the most sensitive antibody assay was an immunoblot from Biotech (95%) and HIV-1 P24 was found infrequently (9.5%). The sensitivities of ELISAs and immunoblot were 100% in individuals with more-developed antibody patterns, and no HIV-1 P24 was detected among them.