Abstract: Objective To evaluate the clinical usefulness of Treponema pallidum IgM Western blot (TP-IgM-WB) test in the diagnosis of neonatal congenital syphilis. Methods Eight cases of neonatal congenital syphilis, whose mothers were diagnosed as syphilis at different pregnant stages, were tested by TRUST, TPPA, FTA-ABS-19S-IgM and TP-IgM-WB. The results and clinical manifestations were analysed. Results Three of 8 cases presented clinical manifestations of congenital syphilis, including typical cutaneous lesions, syphilitic pneumonia, and multi-system failure. The others were asymptomatic. In all 8 cases TP-IgM-WB was positive. Of them 7 cases FTA-ABS-19S-IgM was positive. Six cases (including 3 symptomatic) were positive to all four tests. One case was positive to FTA-ABS-19S-IgM and TP-IgM-WB, but negative to TRUST and TPPA. One case was negative to FTA-ABS-19S-IgM, but positive to TPPA, TP-IgM-WB and TRUST, and TRUST titer was 4 times as high as her mother. Conclusions In view of its high specificity and sensitivity, TP-IgM-WB could be used as a confirmatory test for the diagnosis of both symptomatic and asymptomatic neonatal congenital syphilis.

Key words: Syphilis, congenital, Syphilis serodiagnosis