Congenital syphilis can be best diagnosed by-

Ans. is 'a' i.e., IgM FT A - ABS * As Ig M does not cross placenta, its presence in neonatal serum confirms congenital syphilis and helps differentiating it from seropositivity due to passively tranfered maternal antibodies. The tests to detect IgM are# FTA-ABS (19S IgM FT A-ABS)# Syphilis Capita M test"For measurment of IgM in neonate in whom congenital syphilis is suspected, the syphilis capita M test and the 19S IgM FTA-ABStest are available". - Harrison 16th/e 982Note - 15th/e Harrison says, "No commercially available IgM test is recommeded forevaluation of infant with suspected congenital syphillis" -------- Harrison 17th/e 1043