New lineal immunoenzymatic assay for simultaneous detection of p24 antigen and HIV antibodies.

The aim of this study was to evaluate a new lineal immunoenzymatic assay for the simultaneous detection of HIV-1/HIV-2 antibodies and p24 antigen. A total of 320 serum samples were obtained from individuals infected by HIV (HIV 1, n = 183; HIV 2, n = 2), individuals with risk factors for HIV infection (n =49), recipients of multiple transfusions (n =40), and blood donors (n = 46). The Western blot for detection of HIV antibodies and an enzyme immunoassay for detection of p24 antigen, both established techniques, were used for direct comparison. In cases of recent infection, p24 antigen was generally detected at the same time by the lineal test and the established assay. The p24 antigen sensitivity was about 200 pg of HIV antigen per milliliter. The results seem to indicate that the new test could be used with sufficient reliability for screening biological samples (sensitivity, 99.5%; specificity, 94.8%). Use of the lineal immunoenzymatic assay may shorten the amount of time needed to diagnose acute infection with HIV to approximately 2 weeks.