DETECTION OF HUMAN-IMMUNODEFICIENCY-VIRUS (HIV) TYPE-1 ANTIBODIES BY NEW AUTOMATED MICROPARTICLE ENZYME-IMMUNOASSAY FOR HIV TYPE-1 AND TYPE-2

We compared an automated microparticle double-antigen sandwich enzyme Immunoassay (EIA) for the IMx test system recently developed by Abbott with two established assays (the automated indirect Vidas IgG EIA and the double-antigen sandwich EIA from Murex/Wellcome) devised for the detection of human immunodeficiency virus type 1 (HIV-1) and HIV-2 ant ibodies. A total of 1,078 consecutive serum samples were tested prospe ctively with the three assays, In addition, we used retrospectively se lected panels of serum samples with discrepant results in two differen t screening tests and with indeterminate or positive Western immunoblo t (WB) results, as well as five commercially available HIV-1 seroconve rsion panels, The new assay showed excellent discriminatory characteri stics for the separation of samples from HIV-1-positive and HIV-1-nega tive persons according to Centers for Disease Control and Prevention W E criteria, The sensitivities were 98.1, 92.9, and 96.1% for the new t est and the two other assays, respectively, and the specificities were 99.7, 97.9, and 98.1%, respectively, With the seroconversion panels t his new test was positive several days earlier than the two other assa ys; i.e.,, seroconversion was evident at the peak of p24 antigenemia a nd often several weeks before WE became positive by the most stringent criteria.