HUMAN-IMMUNODEFICIENCY-VIRUS (HIV) ANTIBODIES DETECTED BY NEW ASSAYS THAT ARE ENHANCED FOR HIV-1 SUBTYPE-O

BACKGROUND: Human immunodeficiency Virus type 1 (HIV-1) subtype O infe ctions are not reliably detected by commonly used anti-HIV-1/2 screeni ng assays. Therefore, anti-HIV-1/2 assays have been modified to increa se their sensitivity in detecting antibodies to HIV-1 subtype O. STUDY DESIGN AND METHODS: Two new anti-HIV-1/2 enzyme-linked immunosorbent assays (ELISAs) (Abbott Plus and Ortho Enhanced) were compared with a currently used anti-HIV-1/2 ELISA (Abbott Recombinant) in various seru m panels: 91 Western blot-confirmed anti-HIV-1-positive samples, 20 sa mples from Western blot-confirmed HIV-l-infected patients in log(3) se rial dilutions, and 1463 samples from consecutive, volunteer, nonremun erated blood donors. RESULTS: Among 91 anti-HIV-1 Western blot-positiv e samples, 2 (2.2%) were missed by the Abbott Recombinant ELISA, but a ll 91 were detected by the Abbott Plus and Ortho Enhanced ELISAs. In c ontrast, two discrepant ant samples were found to react in viral lysat e-based assays. In serial dilutions,Ortho Enhanced ELISA was significa ntly less sensitive than the Abbott Recombinant and Abbott Plus ELISAs , with the latter two being of comparable sensitivity. The specificiti es of Abbott Recombinant, Abbott Plus, and Ortho Enhanced ELISAs in 14 63 blood donors were 100, 99.93, and 99.86 percent, respectively. Rout ine testing of 29, 102 donations with the enhanced Abbott Plus ELISA r evealed a specificity of 99.93 percent. CONCLUSION: Two Western blot-c onfirmed anti-HIV-1 positive samples were missed by the Abbott Recombi nant ELISA but detected by the Abbott Plus and Ortho Enhanced ELISAs. The analytic sensitivity of the Ortho Enhanced ELISA was inferior to t hat of both Abbott ELISAs. The specificities of the Abbott Recombinant , Abbott Plus, and Ortho Enhanced ELISAs were comparable.