* Nontreponemal tests include the rapid plasma reagin (RPR), the Venereal Disease Research Laboratory (VDRL), and the toluidine red unheated serum test (TRUST).
¶ Treponemal tests include the fluorescent treponemal antibody absorption (FTA-ABS), the Treponema pallidum particle agglutination (TPPA), the T. pallidum enzyme immunoassay (TP-EIA), or chemiluminescence immunoassay (CIA). These different tests target different antigens.
Δ Treatment of syphilis depends upon the clinical manifestations and the stage of disease (eg, early, late, neurosyphilis). Asymptomatic patients are considered to have latent syphilis and should be treated for early latent (patient has serologic evidence of T. pallidum infection that was acquired within the last 12 months) or late latent disease (the initial infection occurred more than 12 months ago). If the timing of an infection is not known, late latent syphilis is presumed. Refer to UpToDate topic on the treatment and monitoring of syphilis for information on treatment regimens.
◊ False-positive nontreponemal tests can be seen in the setting of pregnancy, an acute event (eg, febrile illness, endocarditis, rickettsial disease), or recent immunization. Test abnormalities attributed to these conditions are usually transitory and typically last for six months or less. Other etiologies include chronic conditions, such as autoimmune disorders (particularly systemic lupus erythematosus), intravenous drug use, chronic liver disease, and underlying HIV disease.