Comparison of assays for antibody to HTLVI.

Indirect immunofluorescence, competitive radioimmunoassay, HTLV I-enzyme linked immunosorbent assay and gelatin particle agglutination Serodia-ATLA were compared in terms of their ability to detect antibody to human T cell leukaemia virus I (HTLV I). The sensitivities were 96.9%, 92%, 97.0%, and 100%, respectively, and the specificities 99.3%, 98.9%, 98.6%, and 96.3%. Particle agglutination was very simple to perform and was the most sensitive, though the least specific test. Antibody titres were 10-100 times higher when measured by particle agglutination than by other tests, and antibody titers were considerably higher in patients with neurological disease related to HTLV I than in those with other conditions. Serodia-ATLA is the method of choice for preliminary screening of specimens for antibody to HTLV I, but positive results must be confirmed by another technique.