PANCE Board Practice Exam

The key idea is that confirming a syphilis infection relies on a test that detects antibodies specific to Treponema pallidum, not just any inflammatory or non-specific antibodies. Non-treponemal tests like RPR and VDRL are useful for screening and for tracking response to therapy because their titers rise with active infection and fall after treatment. However, they can yield false positives and don’t prove infection with Treponema pallidum on their own. A treponemal test, such as FTA-ABS, directly detects antibodies against the organism itself. It has very high specificity for Treponema pallidum, so a positive treponemal test confirms infection rather than merely indicating a reaction that could occur with other conditions. Because these antibodies can remain positive for life, treponemal tests are ideal for confirming whether someone has been infected, even if screening tests were equivocal or if the patient has had prior therapy. NAATs (nucleic acid amplification tests) aren’t the standard confirmatory test for systemic syphilis; they’re more often used in specific situations, such as testing lesion material, and don’t replace a treponemal confirmatory test for typical diagnostic workups. So, the test that serves as the gold standard for confirming syphilis is the treponemal-specific assay, like FTA-ABS.