With positive nontreponemal test results, findings are quantified and expressed as titers. Because titers reflect disease activity, they increase during early syphilis and often exceed levels of 1 :32 in secondary syphilis. Following treatment of primary and secondary syphilis, serological testing at 3 to 6 months usually confirms a fourfold drop in VDRL or RPR titers (Rac, 2014a). Because VDRL titers do not correspond directly to RPR titers, consistent use of the same test for surveillance is recommended. hose with treatment failure or reinfection may lack this expected decline. Importantly, some successfully treated patients may still exhibit persistently low-level positive titers, which are referred to as "serofast." his state is more likely in older individuals, those with lower initial nontreponemal antibody titers, and those with later stages of syphilis (Seia, 2015).
The second type of serological testing is trep0 nemal-specic.
It seeks patient antibodies formed specifically against T palidum. he antibodies detected by treponemal assays appear up to a few weeks earlier than those detected by nontreponemal tests (Levett, 2015). Tests includes the fluorescent treponemalantibody absorption tests (FTA-ABS), the T palidum passive particle agglutination (TP-PA) test, and various immunoassays (Association of Public Health Laboratories, 2015). O/note, these treponemal-speciic tests generaly remain positive throughout lie.
Each of the serological tests has limitations including falsepositive and -negative results. Traditionally, nontreponemal tests have been used for screening in the United States, and results are then conirmed by a specific treponemal test. Within the past several years, some laboratories have implemented a reverse screening algorithm, namely, screening first with a treponemalspecific test (Binnicker, 2012; Centers for Disease Control and Prevention, 2011). Both approaches are efective if there is a program for appropriate screening, follow-up, and treatment.
In contrast to these tests, rapid "point-of-care" (POC) syphilis screening of blood or serum samples is being developed (Singh, 2015; Tucker, 2010). hese may be best used for women with limited prenatal care. Most tests are treponemalspecific, and positive POC results can then be confirmed by a laboratory nontreponemal test. In hard-to-reach populations, some countries immediately treat women with positive POC results. This practice, however, risks overtreating previously cured women who still have residual persistent treponemal antibodies. his limitation may be overcome by newer POC dual tests, which simultaneously assess nontreponemal and treponemal antibodies (Causer, 2015).
Following maternal diagnosis, sonographic evaluation is performed for fetuses >20 weeks' gestation to search for signs of congenital syphilis. Rac and associates (20 14b) noted that 31 percent of infected women diagnosed at � 18 weeks' gestation had abnormal fetal sonographic indings. Hepatomegaly, placental thickening, hydramnios, ascites, hydrops fetalis, and elevated middle cerebral artery Doppler velocimetry measurements are indicative of fetal infection. Before 20 weeks, treatment is highly successful, and sonographic findings are rare (Nathan, 1997).
For fetuses of viable age with sonographic findings, antepartum fetal heart rate monitoring prior to treatment is recommended. Spontaneous late decelerations or a nonreactive tracing likely reflects an extremely ill fetus that may poorly tolerate a Jarisch-Herxheimer reaction, described next. In this extreme case, consultation with a neonatologist regarding a plan of delaying treatment, pursuing delivery, and then treating in the nursery is a consideration (Wendel, 2002).