How sensitive are the commercial assays for anti-HTLV III/LAV?

The sensitivity of nine commercial assays, Western blot, and a newly developed monoclonal antibody-based assay for antibody to human T lymphotropic virus type III/lymphadenopathy associated virus (anti-HTLV III/LAV) were evaluated using a panel of mainly weak-positive sera. In tests on 20 sera three commercial assays and a monoclonal-based assay, representing two different solid-phase methodologies, were found to be more sensitive than Western blot. Our findings suggest that Western blot cannot be depended upon as the sole confirmatory test for anti-HTLV III/LAV. The continued use of the more sensitive enzyme-linked immunosorbent assays (ELISAs), particularly those of dissimilar methodology, would be a more valid approach to confirmatory testing.