Utility and limitations of T. gondii-specific IgM serum antibodies in the diagnosis of congenital toxoplasmosis

Congenital toxoplasmosis is associated with considerable morbidity when untreated. From the time of the discovery of T. gondii-specific IgM in infants, establishing the diagnosis of this infection has included the detection of T. gondii-specific IgM antibodies in serum of the newborn infant. However, whether this differs and the robustness of this test in different populations and regions has not been defined. Lago, Oliveira, and Bender describe their experience with the presence of T. gondii IgM in sera obtained from congenitally infected infants whose mothers were tested prenatally or in which only the infants themselves were tested in the newborn period at a screening program. They also noted the duration that the anti-T. gondii IgM could still be detected in sera from infants with congenital toxoplasmosis, in a carefully performed and well-described study. The investigators used an IgM enzyme linked fluorescent assay (ELFA) (BioMérieux Marcy l’Etoile, France) to detect T. gondii-specific IgM in serum and a fluorometric