[Specificity of first and second generation HIV-1 antibody screening tests]

Among 9867 sera tested between January and April 1987 by Abbott HTLV-III EIA (cell culture-derived antigen) 155 reacted repeatedly positive. 22% of these could not be confirmed, while 77% could be confirmed by other tests. The results of 2 sera remained equivocal. Subsequently Abbott recombinant HTLV-III EIA was used and until August of the same year 184 out of 11508 sera gave reproducible positive results. 12% of these could not be confirmed, while 86% could be confirmed. The results of 3 sera remained equivocal. False positive results were found in 0.34% of all sera examined by the test of the first generation, whereas the percentage in the second generation test was 0.19. Despite the higher specificity of the ELISA with antigen prepared by recombinant gene technology, there is further need for reliable confirmatory tests.