Which tests are non-treponemal and commonly used for screening in syphilis?

Which tests are non-treponemal and commonly used for screening in syphilis?

• A. VDRL and RPR tests
• B. FTA-ABS test
• C. TPPA test
• D. Darkfield microscopy

Answer: (A)

Non-treponemal screening tests target antibodies that react with cardiolipin rather than the actual syphilis bacterium. VDRL and RPR fit this pattern: they’re inexpensive, rapid, and easily scalable for screening, and their results can be quantified to monitor treatment response. Because they’re not specific to Treponema pallidum, they can yield false positives in conditions such as autoimmune diseases, certain infections, and pregnancy, which is why a positive screen is followed by a confirmatory treponemal test (like FTA-ABS or TPPA) to establish true infection. Treponemal tests are more specific and tend to remain positive for life after infection, but they’re not used for initial screening. Darkfield microscopy directly visualizes the organism and isn’t used for routine screening. Thus, the non-treponemal tests used for screening are VDRL and RPR.

Non-treponemal screening tests target antibodies that react with cardiolipin rather than the actual syphilis bacterium. VDRL and RPR fit this pattern: they’re inexpensive, rapid, and easily scalable for screening, and their results can be quantified to monitor treatment response. Because they’re not specific to Treponema pallidum, they can yield false positives in conditions such as autoimmune diseases, certain infections, and pregnancy, which is why a positive screen is followed by a confirmatory treponemal test (like FTA-ABS or TPPA) to establish true infection. Treponemal tests are more specific and tend to remain positive for life after infection, but they’re not used for initial screening. Darkfield microscopy directly visualizes the organism and isn’t used for routine screening. Thus, the non-treponemal tests used for screening are VDRL and RPR.