Comparing three treponemal tests for syphilis screening.

We compared the performance and ease of use for three high-throughput treponemal immunoassays: Phoenix Biotech Trep-Sure Total Antibody EIA, Siemens ADVIA® Centaur Syphilis Assay, and DiaSorin LIAISON® Treponema Assay. One thousand serum samples submitted for routine screening were used in this study. Each assay demonstrated comparable sensitivity, specificity, and percent agreement (98-100%) compared with Treponema pallidum particle agglutination (TP-PA). Thus, treponemal immunoassays are an acceptable alternative for syphilis screening or confirmatory testing. Batch sizes and technologist active time varied between each treponemal immunoassay; the chemiluminescence platforms offered significantly greater ability to batch (random access vs. fixed batch sizes) in less time. When we compared the results obtained using a reverse algorithm approach to those obtained using a traditional algorithm, we found that the reverse algorithm identified 38 additional seropositive individuals that were not detected using the traditional algorithm. Clinical evaluation was useful for resolving cases with discordant serology.