IgG Western blot as a confirmatory test in early syphilis

Sensitivity and specificity of IgG detection by Western blotting performed with a lysate of Treponema pallidum whole cells were compared with those of the most common assays used in the laboratory diagnosis of syphilis, i. e. fluorescent treponemal antibody absorption test (FTA-ABS) and treponemal h aemagglutination assay (TPHA). Thirty-five serum samples obtained from twen ty-one patients with a clinical diagnosis of early syphilis, based on the p resence of typical chancre or skin or mucous membrane lesions, were studied . In addition, thirty blood samples from donors, ten sera positive for Borr elia burgdorferi and five positive for Leptospira interrogans were tested a s controls. The clinical diagnosis was the reference method used to compare the performance of the serological tests. Western blotting performed with a sensitivity and specificity of 100%, whereas the corresponding sensitivit y and specificity for FTA-ABS were 88.5% and 98%, respectively. The perform ance of TPHA showed a sensitivity of 86% and a specificity of 100%.