A presumptive diagnosis of syphilis requires use of 2 laboratory serologic tests: a nontreponemal test (ie, Venereal Disease Research Laboratory [VDRL] or rapid plasma reagin [RPR] test) and a treponemal test (ie, the T pallidum passive particle agglutination [TP-PA] assay, various EIAs, chemiluminescence immunoassays [CIAs] and immunoblots, or rapid treponemal assays).1-3 Use of only one type of serologic test (nontreponemal or treponemal) is insufficient for diagnosis and can result in false negative results among persons tested during primary syphilis and false positive results among persons without syphilis or with previously treated syphilis.1,2
Both the CDC and the United States Preventive Services Task Force (USPSTF) recommend routine syphilis screening for men who have sex with men (MSM), individuals with HIV, and other individuals at increased risk for syphilis (Table 1). Syphilis screening is also recommended for individuals being considered for or receiving HIV PrEP because syphilis is associated with higher risk of HIV infection.4 MSM are disproportionately impacted by syphilis, accounting for 47% of all male primary and secondary syphilis cases in the US in 2021. The prevalence of syphilis is also higher in certain geographic regions and among certain races and ethnicities.2,3 For most at-risk populations, screening is recommended at least annually, with more frequent screening (eg, every 3-6 months) should be considered based on individual risk and local prevalence.2-3