The U.S. Preventive Services Task Force (USPSTF) strongly recommends that clinicians screen persons at increased risk for syphilis infection. (A)
The USPSTF strongly recommends that clinicians screen all pregnant women for syphilis infection. (A)
The USPSTF recommends against routine screening of asymptomatic persons who are not at increased risk for syphilis infection. (D)
Clinical Considerations
Populations at increased risk for syphilis infection (as determined by incident rates) include men who have sex with men and engage in high-risk sexual behavior, commercial sex workers, persons who exchange sex for drugs, and those in adult correctional facilities.
Persons diagnosed with other sexually transmitted diseases (STDs) (i.e., chlamydia, gonorrhea, genital herpes simplex, human papilloma virus, and HIV) may be more likely than others to engage in high-risk behavior, placing them at increased risk for syphilis; however, there is no evidence that supports the routine screening of individuals diagnosed with other STDs for syphilis infection.
Nontreponemal tests commonly used for initial screening are the Venereal Disease Research Laboratory (VDRL) or Rapid Plasma Reagin (RPR), followed by a confirmatory fluorescent treponemal antibody absorbed (FTA-ABS) or T. pallidum particle agglutination (TP-PA). The optimal screening interval in average- and high-risk persons has not been determined.
Follow up serologic tests should be obtained to document initial decline after treatment. These follow up tests should be performed using the same nontreponemal test initially used to document infections (e.g., VDRL or RPR) to ensure comparability.
All pregnant women should be tested at their first prenatal visit. For women in high-risk groups, repeat serologic testing may be necessary in the third trimester and at delivery
Interpretation of Serologic Tests for Syphilis
A period of 1 to 4 weeks may elapse between the appearance of the primary chancre and the detection of a non-treponemal reaction. Treponemal reactions become positive before non-treponemal reactions.
The non-treponemal test is a good follow-up indicator because the titer reflects the activity of the disease. Following treatment, it should show a regular decline until it becomes negative or stabilizes at a low level (<= 1:8).
Serology may remain positive for life in persons who have previously contracted syphilis and been adequately treated.
The non-treponemal test may be falsely positive in certain clinical situations including viral infections (e.g., mononucleosis), bacterial infections (e.g., pneumonia, tuberculosis), chronic disease (e.g., collagen vascular disease), and in the elderly.
Treponemal tests may be falsely positive in certain situations, including viral infections and collagen vascular disease.
