Evaluation of commercial HTLV-1 test kits by a standard HTLV-1 serum panel.

To evaluate the performance of currently available test kits for human T-cell lymphotropic virus type 1 (HTLV-1), we examined two particle agglutination (PA) tests and nine enzyme immunoassays (EIA) using a standard serum panel consisting of HTLV-1-positive and HTLV-1-negative sera that had been characterized by immunofluorescence and the polymerase chain reaction (PCR). The PA kits exhibited 94.0-100.0% sensitivity and 99.5-100.0% specificity; the sensitivity range was ascribed to the quality of the HTLV-1 antigens coated on the particles. The EIA kits had 99.5-100% sensitivity and 98.5-100% specificity; the 98.5%-99.5% specificity exhibited by five of the EIA kits could have been due to nonspecific reactions that were detected through use of an inadequate cut-off value and the use of recombinant proteins. It can be concluded that the sensitivity of the currently available PA and EIA kits is sufficient to permit their use for screening purposes; however, the specificity of some EIA kits should be optimized.