Evaluation of the fluorescent treponemal antibody absorption test for detection of antibodies (immunoglobulins G and M) to Treponema pallidum in serologic diagnosis of syphilis

We compared the fluorescent treponemal antibody-absorption (FTA-ABS) (immunoglobulin (Ig)G + IgM) assay with the (micro-) Treponema pallidum haemagglutination assay (TPHA), the T. pallidum particle agglutination assay (TPPA), the Murex syphilis ICE (ICE) enzyme-linked immunosorbent assay (ELISA), the Diesse Enzywell TP (TP) (ELISA) using 122 serum samples and the Western blot (WB) assay using 42 serum samples whose results were inharmonious with other tests. Additionally, the Captia syphilis-M (IgM) (ELISA) were performed. All sera had already been examined by the rapid plasma reagin (RPR) card test, a non-treponemal test and the TPHA, a treponemal test using routine screening tests. Agreements of the FTA-ABS with the TPHA test, the TPPA test, the ICE test and the TP test were 97.5%, 95.9%, 98.3% and 98.3%, respectively. The results suggest that the FTA-ABS test is a useful confirmatory test, but can be inadequate as a confirmatory test for serologic diagnosis of syphilis by giving equivocal and false-negative results even rarely.