Which statement about syphilis testing is false?

Which statement about syphilis testing is false?

• A. A non-treponemal test is used for screening
• B. A treponemal test is used for confirmation after a positive non-treponemal test
• C. Both non-treponemal and treponemal tests are used in diagnosis
• D. A non-treponemal test alone is sufficient for diagnosis

Answer: (D)

Screening for syphilis uses a non-treponemal test because it’s inexpensive and sensitive across many stages of infection, but it isn’t specific for Treponema pallidum. Non-treponemal tests can give false positives in conditions like autoimmune diseases or pregnancy and can miss very early or very late infections. Because of these limitations, a positive non-treponemal result must be followed by a treponemal test that detects antibodies specific to the bacterium, which confirms true exposure to syphilis. Treponemal tests (such as FTA-ABS or TP-PA) tend to remain positive for life, even after treatment, so they’re excellent for confirmation but not for gauging current activity or response to therapy. In many settings, both tests are used in diagnosis, or a treponemal test may be used first in a reverse algorithm. Therefore, the statement that a non-treponemal test alone is sufficient for diagnosis is false because non-treponemal tests lack enough specificity and cannot distinguish past from active infection without treponemal confirmation and clinical context.

Screening for syphilis uses a non-treponemal test because it’s inexpensive and sensitive across many stages of infection, but it isn’t specific for Treponema pallidum. Non-treponemal tests can give false positives in conditions like autoimmune diseases or pregnancy and can miss very early or very late infections. Because of these limitations, a positive non-treponemal result must be followed by a treponemal test that detects antibodies specific to the bacterium, which confirms true exposure to syphilis. Treponemal tests (such as FTA-ABS or TP-PA) tend to remain positive for life, even after treatment, so they’re excellent for confirmation but not for gauging current activity or response to therapy. In many settings, both tests are used in diagnosis, or a treponemal test may be used first in a reverse algorithm.

Therefore, the statement that a non-treponemal test alone is sufficient for diagnosis is false because non-treponemal tests lack enough specificity and cannot distinguish past from active infection without treponemal confirmation and clinical context.