A biological false-positive reaction is least likely with which test for syphilis?

A biological false-positive reaction is least likely with which test for syphilis?

• A. VDRL
• B. Fluorescent T. pallidum antibody absorption test (FTA-ABS)
• C. RPR
• D. All are equally likely to detect a false-positive result

Answer: (B)

The fluorescent T. pallidum antibody absorption test (FTA-ABS) is considered to be a more specific test for syphilis compared to the other options listed. This test directly detects antibodies to Treponema pallidum, the causative agent of syphilis, and it undergoes a more stringent process to confirm the presence of these specific antibodies. As a result, it is less likely to produce a biological false-positive reaction, which occurs when a test indicates the presence of syphilis antibodies without an actual infection. In contrast, the VDRL and RPR tests are non-treponemal tests that measure the presence of non-specific antibodies. These tests are more prone to false-positive results due to various factors unrelated to syphilis, such as other infections, autoimmune diseases, and even certain pregnancy conditions. Given this context, the FTA-ABS maintains a higher specificity and reliability in diagnosing syphilis, making it the test that is least likely to yield false-positive results.

The fluorescent T. pallidum antibody absorption test (FTA-ABS) is considered to be a more specific test for syphilis compared to the other options listed. This test directly detects antibodies to Treponema pallidum, the causative agent of syphilis, and it undergoes a more stringent process to confirm the presence of these specific antibodies. As a result, it is less likely to produce a biological false-positive reaction, which occurs when a test indicates the presence of syphilis antibodies without an actual infection.

In contrast, the VDRL and RPR tests are non-treponemal tests that measure the presence of non-specific antibodies. These tests are more prone to false-positive results due to various factors unrelated to syphilis, such as other infections, autoimmune diseases, and even certain pregnancy conditions. Given this context, the FTA-ABS maintains a higher specificity and reliability in diagnosing syphilis, making it the test that is least likely to yield false-positive results.