In treponemal testing for syphilis, which option is a treponemal test?

In treponemal testing for syphilis, which option is a treponemal test?

• A. RPR
• B. VDRL
• C. FTA-ABS
• D. RPR and VDRL

Answer: (C)

Treponemal testing looks for antibodies specifically against Treponema pallidum, the bacterium that causes syphilis. Among the options, the Fluorescent Treponemal Antibody Absorption test (FTA-ABS) is a true treponemal test because it detects antibodies directed against T. pallidum itself and tends to remain positive for life after infection, making it useful for confirming disease after a reactive screen. The other tests shown are non-treponemal tests; they detect antibodies to cardiolipin and are used mainly for initial screening and for monitoring treatment response, but they are not specific to Treponema pallidum and can yield false positives or become nonreactive after therapy. Therefore, FTA-ABS is the treponemal test.

Treponemal testing looks for antibodies specifically against Treponema pallidum, the bacterium that causes syphilis. Among the options, the Fluorescent Treponemal Antibody Absorption test (FTA-ABS) is a true treponemal test because it detects antibodies directed against T. pallidum itself and tends to remain positive for life after infection, making it useful for confirming disease after a reactive screen. The other tests shown are non-treponemal tests; they detect antibodies to cardiolipin and are used mainly for initial screening and for monitoring treatment response, but they are not specific to Treponema pallidum and can yield false positives or become nonreactive after therapy. Therefore, FTA-ABS is the treponemal test.