Advantages and limitations of current diagnostic laboratory approaches in syphilis and congenital syphilis

Pharmacokinetics of single dose doxycycline in the rectum, vagina, and urethra: implications for prevention of bacterial sexually transmitted infections

“…Because syphilis diagnosis depends on seroconversion or increase in antibody titres, it is unclear if doxycycline will affect syphilis diagnostic testing in some individuals through delays in seroconversion or reductions in antibody titers. 28 …”