Syphilis test (FTA-ABS): The fluorescent treponemal antibody absorbed (FTA-ABS) test for syphilis is a blood serum screening test designed to demonstrate the presence or absence of specific antibodies directed against the organism (Treponema pallidum) responsible for syphilis.
The test detects the majority but not all cases of the disease. It is thus a way of screening for the disease.
A negative FTA-ABS test result is consistent with a person not having syphilis. However, a person may have a negative FTA-ABS test result while in the early (primary) stages of the disease. In the middle (secondary) stage of syphilis, the FTA-ABS test is most reliable and is reportedly positive in 100% of cases.