For primary syphilis, a low RPR (0-16) was correlated with a higher detection rate of TP-DNA, whereas for secondary syphilis, the higher detection rate of blood TP-DNA was correlated with higher blood RPR titers (at or beyond 32).
During 2012-2014, we screened 1625 MSM from Lima, Peru, for syphilis infection and enrolled 370 MSM with symptomatic primary or secondary syphilis (n=58) or asymptomatic latent syphilis diagnosed by serology (rapid plasma reagin, RPR, and Microhemagglutination assay for Treponema pallidum antibody; n=312).