Evaluation of the automated VIDAS system for the detection of anti-HIV-1 and anti-HIV-2 antibodies

Abstract

A new, modular ‘walk away’ systen for HIV 1 and HIV 2 antibody detection (VIDAS HIV 1 + 2 enzyme linked fluorescent assay) was compared with EIAs (Wellcozyme HIV recombinant, Wellcome; and Enzygnost HIV 1 + 2, Behringwerke) and Western blot (New LAV I Blot; Pasteur). 434 serum samples from HIV seropositive patients at different stages of disease, individuals at high risk, patients with conditions unrelated to AIDS and healthy blood donors were used for this evaluation together with 4 seroconversion panels, 4 serum dilution series and ‘difficult’ sera (repeatedly positive results in EIA, but negative or indeterminate by Western blot; n = 87). With the Western blot as the reference assay, the overall sensitivity of VIDAS HIV 1 + 2 and the alternative EIAs was 100%. Significant differences in sensitivity between the 3 EIAs were not observed for the antibody detection in the seroconversion panels and the dilution series. The specificity of VIDAS HIV 1 + 2, Enzygnost and Wellcozyme were 93.5%, 89.6% and 92.4% respectively if Western blot strips were interpreted according to CDC-criteria. A high rate of false positive results was obtained with the 3 EIAs since serum samples were not selected randomly and a large collective of ‘difficult sera’ was investigated. So-called ‘walk away’ systems like VIDAS HIV 1 + 2 offer a rapid screening for HIV antibody detection for routine laboratory diagnosis.