Congenital syphilis can be best diagnosed by:
IgM-FTA-Abs test is a modification to identify fetal IgM and clarify the diagnosis of congenital syphilis or a re-infection. Ref: Color Atlas of Dermatology By Main Rocken, Main Schaller - 2012
IgM FTAabs
IgG FTAabs
VDRL
TPI