Diagnosis of Toxoplasmosis in Pregnant Women by IgG Avidity Assay

Background: Toxoplasma gondii is an obligate intracellular parasite that has ability to infect most warm blooded vertebrates. primary infection during pregnancy can lead to transmission of the infection to the fetus, with associated symptoms. the aim of this study was to compare methods for serological measurement of anti-toxoplasma IgG and IgM in pregnant women and also tested seroconversion mothers by IgG avidity, and finally comparing the results of these experiments with each others. Methods: In this comparative analytical study, from 2120 pregnant women referred to karaj medical laboratories (in 1392 years) serum specimens were obtained and tested with Chemiluminescence (CLIA) & (Enzyme Linked Fluorescent Assay) ELFA methods. Then for detection of chronic and acute infection, serum IgM+ specimens tested by IgG Avidity assay. Results: In this study, out of 1362 cases of 2120 pregnant women were IgG+ with ELFA & CLIA methods. In IgM ELFA method, 38 samples were positive and 2 samples were borderline. In IgM CLIA method, 37 samples were positive and1samples were borderline. In IgG Avidity, from 40 serum samples, 15 samples were low aviditiy, 20 samples were high avidity and 5 samples were borderlines. In IgG Avidity positive predictive value were 57%. Conclusion: Every pregnant women needs to do anti-toxoplasma IgG and IgM tests. after considering all valid serological and molecular methods for deciding to treatment or termination of gestation must be used the other sensitive and reliable parasitology methods such as inoculation of susceptible lab animal and PCR on amniotic fluid