The fluorescent treponemal antibody absorption (FTA-ABS) test is a blood test that checks for the presence of antibodies to Treponema pallidum bacteria which causes Syphilis. Syphilis is a sexually transmitted infection (STI) that's spread through direct contact with syphilitic sores, these sores are most often present on the penis, vagina or rectum. The FTA-ABS test is often performed after other tests that screen for syphilis, such as the rapid plasma regain (RPR) and venereal disease research laboratory (VDRL) tests. The ABS suffix refers particularly to a processing step used to remove nonspecific anti spirochetal antibodies present in normal serum.