Enzywell recombinant enzyme immunoassay for the serological diagnosis of syphilis

The aim of this study was to evaluate Enzywell TP, a new rapid enzyme immun oassay (EIA) that uses 2 recombinant Treponema pallidum antigens for the se rological diagnosis of syphilis. Specificity was evaluated by screening 105 5 unselected bloods requesting serological tests for syphilis in parallel w ith Enzywell TP and the Syphilis ICE EIA which is our standard screening te st for syphilis. Sensitivity was evaluated using a panel of 159 known trepo nemal sera representing various stages of syphilis and 5 treponemal sera de tected on screening. The specificity of Enzywell TP on initial and repeat t esting (99.6% and 99.7% respectively) was similar to that of the Syphilis I CE test (99.8% and 99.9% respectively). The sensitivity of Enzywell TP (100 %) was similar to that of Syphilis ICE (99.4%): both tests were significant ly more sensitive (P=0.01) than the fluorescent antibody absorbed test (94. 5%) but not the T. pallidum particle agglutination (TPPA) assay (99.4%). Bo th Enzywell TP and Syphilis ICE were positive with sera from 16 known HIV-i nfected patients who had been treated for syphilis many years previously (m ean 9.4 years) confirming the value of these tests in excluding previous sy philis in HIV-infected individuals. We conclude that the Enzywell recombina nt EIA is simple, rapid, highly sensitive and specific, and is a welcome ad dition to the range of currently available diagnostic tests for syphilis.