Nontreponemal tests for syphilis

A nontreponemal test (NTT) is a blood test for diagnosis of infection with syphilis. Nontreponemal tests are an indirect method in that they detect biomarkers that are released during cellular damage that occurs from the syphilis spirochete. In contrast, treponemal tests look for antibodies that are a direct result of the infection thus, anti-treponeme IgG, IgM and to a lesser degree IgA. Nontreponemal tests are screening tests, very rapid and relatively simple, but need to be confirmed by treponemal tests.^[1] Centers for Disease Control and Prevention (CDC)-approved standard tests include the VDRL test (a slide test), the rapid plasma reagin (RPR) test (a card test), the unheated serum reagin (USR) test, and the toluidine red unheated serum test (TRUST).^[2] These have mostly replaced the first nontreponemal test, the Wassermann test.^{[citation needed]}