ELISA for Detection of IgM Antibody to Treponema Pallidum for the Diagnosis of Primary Syphilis

In order to explore the significance of the capture enzyme-linked immunosorbent assay for detection of specific IgM antibody(IgM-Capture-ELISA) to treponema pallidum for the diagnosis of primary syphilis, 73 sera from 73 patients (67 with primary syphilis, 3 with asymptomatic neurosyphilis, 3 with unknown latent syphilis) and 3 CSF samples from 3 asymptomatic neurosyphilis patients and 26 normal sera from noninfected controls were examined by Capture-IgM-ELISA, RPR and TPPA. The results showed that specificity of IgM-Capture-ELISA, RPR and TPPA tests was 100%, 88.5% and 100%, respectively. IgM-Capture-ELISA exhibited greater sensitivity(95.5%) compared to RPR and TPPA (both 83.6%). In addition, 2 of 3 sera with unknown latents syphilis showed positive and 2 of 3 CSF samples with asymptonatic neurosyphilis showed positive by IgM-Capture-RLISA. These suggest that the clinical value of IgM-Capture-ELISA is better than those of RPR and TPPA in diagnosis of primary syphilis and is not very good in diagnosis of asymptomatic neurosyphilis and unknown latent syphilis.