Sexual Health
Labcorp offers timely, accurate and convenient screening options that can help curb rising STI rates in the U.S.
After a long period of decline in the U.S., syphilis cases continue to rise.1
The national rate of primary and secondary syphilis has increased almost every year since 2001. In 2019, a total of 38,992 cases of syphilis were reported, reflecting a 11.2% increase compared to 2018.1
Congenital syphilis has similarly increased in prevalence. Preliminary CDC data showed 2,100 cases of newborn syphilis in 2020.2 In 2010, 29 U.S. states reported one or more cases. In 2019, the number of states reporting congenital syphilis cases rose to 43.3
Per the CDC-recommended algorithm, initial testing is done with a treponemal assay (EIA or CIA) followed by a quantitative nontreponemal test for confirmation (quantitative RPR or other nontreponemal test). Discordant samples are resolved on the basis of a TPPA assay.
All positive nontreponemal tests must be quantified at time of treatment, as titers are used to monitor treatment success.4
On December 20, 2021, CDC published a letter acknowledging the FDA alert of the potential for false positives of RPR results and reminding the healthcare community of the importance of confirming reactive RPR results with treponemal antibody testing.5 False-reactive RPR test results have historically been observed in individuals with autoimmune disorders, systemic infections unrelated to syphilis, (e.g., tuberculosis, rickettsial diseases, HIV, and endocarditis) as well as following immunization (particularly for smallpox) and during pregnancy. 6
The CDC-recommended algorithms for the screening and diagnosis of syphilis include both treponemal and non-treponemal assays. Labcorp offers both the Reverse syphilis screening algorithm and the traditional syphilis screening algorithm.