Performance of rapid syphilis tests in venous and fingerstick whole blood specimens

Objective: Rapid syphilis screening could facilitate case-identification during U.S. outbreaks. Goal: The goal of this study was to determine the performance of 3 rapid syphilis tests in whole blood specimens in the laboratory and in patients at a sexually transmitted disease (STD) clinic. Study: We tested whole blood samples from STD clinic patients with 3 rapid tests and compared results with the serum treponemal pallidum particle agglutination (TP-PA) test. We evaluated the best performing of the 3 rapid tests on fingerstick specimens from STD clinic patients. Results: The Abbott Determine TP (n = 127) had the highest sensitivity (88%; 95% confidence interval [CI], 81-96%) and lowest rate of indeterminate tests (0.8%), followed by Guardian Biosciences One Step (n = 116) (sensitivity 72%; 95% CI, 60-84%; indeterminate 6.5%), and Phoenix BiotechTrep-Strip IV (n = 71) (sensitivity 70%; 95% CI, 54-85%; indeterminate 30.3%). All 3 tests were 100% specific. The Abbott Determine TP showed excellent performance on fingerstick specimens (n = 99), exhibiting 100% sensitivity (95% CI, 93-100%), 100% specificity, and 2.9% indeterminate. Conclusions: The Abbott Determine TP test was an easy and accurate test that could facilitate rapid detection of syphilis in at-risk patients.