Clinical evaluation of four recombinant Treponema pallidum antigen-based rapid tests in the diagnosis of syphilis.

Objective: To assess the sensitivity, specificity, and feasibility of 4 recombinant Treponema pallidum antigen-based rapid tests in the diagnosis of syphilis.

Methods: A total of 970 outpatients were selected from the Sexually Transmitted Diseases Centre of Peking Union Medical College Hospital. Venous blood was collected and serum was extracted. T. pallidum antibodies in whole blood, anticoagulant whole blood, and serum were detected using 4 recombinant T. pallidum antigen-based rapid tests. T. pallidum haemagglutination test (TPHA) was considered as the gold standard for the detection of T. pallidum specific antibodies in serum. The sensitivities and specificities of four methods were analyzed.

Results: The sensitivities and specificities of Abbott Determine Syphilis TP test, SD-BIOLINE Syphilis 3.0 test, VISITECT-SYPHILIS test, and Syphicheck-WB test for serum specimens were 100% and 98.9%, 95.7% and 98.0%, 94.6% and 98.2%, 68.1% and 98.9%; for whole blood were 74.1% and 99.5%, 87.9% and 99.4%, 73.2% and 99.7%, 64.7% and 99.7%. The observed sensitivities of the 4 rapid diagnosis tests were not significantly different with TPHA (P > 0.05).

Conclusions: The 4 rapid tests show good performance and characteristics in the diagnosis of syphilis. Furthermore, they are more sensitive for serum specimens than whole blood.