Rapid Syphilis Test Evaluated as Tool for Public Health Programs

For this evaluation, patients seeking sexually transmitted diseases (STD) testing at the Florida Department of Health STD clinic in Escambia County during March 11 to April 21, 2016, were tested for syphilis using the SHC on blood specimens obtained by fingerstick; a venous blood specimen was drawn concurrently and submitted for treponemal and testing at the state public health laboratory.

Trep-Sure qualitative enzyme immunoassay (EIA) reference treponemal test was used as the standard for “true” positive or negative treponemal test results, when evaluating the SHC. The rapid plasma reagin (RPR) card for syphilis was also tested. The SHC was used to screen 202 patients for syphilis. Among these patients, 171 (85%) were nonreactive on all syphilis tests (SHC, EIA, and RPR), 26 (13%) had a reactive SHC, and five (2%) had a nonreactive SHC, but had one or more reactive tests at the state laboratory.

Among the 26 reactive SHCs, 10 (38%) had a reactive EIA (six had a reactive RPR), and 16 (62%) were not confirmed by EIA or RPR at the state laboratory. For the six reactive SHC patients with reactive EIA and reactive RPR, three were staged as secondary syphilis, one as primary syphilis, one as early latent syphilis, and one was a previously treated positive with no increase in titer since last testing. Among the five specimens that were reactive on other tests but SHC nonreactive, only one was both RPR (1:8 serum dilution) and EIA reactive. The sensitivity of SHC was 71.4% when compared with the Trep-Sure (EIA) reference treponemal test. The specificity of the SHC compared with the reference treponemal test was 91.5%. The study was published on October 28, 2016, in the journal Morbidity and Mortality Weekly Report.

Related Links:
Florida Department of Health
The Centers of Disease Control and Prevention