FTA-ABS is a test used to detect antibodies associated with which infection?

FTA-ABS is a test used to detect antibodies associated with which infection?

• A. Fluorescent Treponemal Antibody Absorption (syphilis)
• B. Rapid Plasma Reagin test
• C. Fluorescent Treponemal Antigen
• D. Treponemal Pallidum Hemagglutination

Answer: (A)

FTA-ABS stands for Fluorescent Treponemal Antibody Absorption. It specifically detects antibodies against Treponema pallidum, the bacterium that causes syphilis. The test uses absorbed patient serum and fixed T. pallidum antigens, then adds a fluorescent anti-human antibody to reveal binding under a fluorescence microscope. A positive result means the person has antibodies directed at the syphilis-causing organism, confirming infection. This treponemal test is used after a positive screening test (like VDRL or RPR) because it is highly specific for Treponema pallidum. Keep in mind that treponemal antibodies often persist for life, so FTA-ABS can remain positive even after successful treatment, unlike non-treponemal tests whose titers may wane. The rapid plasma reagin test detects non-specific reagin antibodies to cardiolipin and is used mainly for screening, not as the confirmatory test; other treponemal tests (like TPHA) also detect antibodies to T. pallidum but FTA-ABS is the classic fluorescence-based confirmatory option.

FTA-ABS stands for Fluorescent Treponemal Antibody Absorption. It specifically detects antibodies against Treponema pallidum, the bacterium that causes syphilis. The test uses absorbed patient serum and fixed T. pallidum antigens, then adds a fluorescent anti-human antibody to reveal binding under a fluorescence microscope. A positive result means the person has antibodies directed at the syphilis-causing organism, confirming infection. This treponemal test is used after a positive screening test (like VDRL or RPR) because it is highly specific for Treponema pallidum. Keep in mind that treponemal antibodies often persist for life, so FTA-ABS can remain positive even after successful treatment, unlike non-treponemal tests whose titers may wane. The rapid plasma reagin test detects non-specific reagin antibodies to cardiolipin and is used mainly for screening, not as the confirmatory test; other treponemal tests (like TPHA) also detect antibodies to T. pallidum but FTA-ABS is the classic fluorescence-based confirmatory option.