Maternal IgG avidity and IgM detected by blot as diagnostic tools to identify pregnant women at risk of transmitting cytomegalovirus

In this study, we determined the avidity index (AI) of anticytomegalovirus (CMV) immunoglobulin G (IgG) and the anti-CMV immunoglobulin M (IgM) profil e in 124 pregnant women, 87 of whom were considered at risk of transmitting CMV infection to their offspring and 37 of whom were at no risk. IgG avidi ty and blot for IgM were performed on two serum samples from each woman, at 6-18 weeks' gestation and at 20-23 weeks' gestation. Pregnancy outcomes we re monitored. The results obtained showed that the determination of anti-CM V IgG avidity at 6-18 weeks' gestation can identify all women who would hav e an infected fetus/newborn (100% sensitivity), whereas IgM detected by blo t had poorer results (69% sensitivity). Interestingly, at 20-23 weeks' gest ation, the sensitivity of IgM detection by blot was higher than that obtain ed by avidity (75% and 63%, respectively) and the combination of IgG avidit y and IgM by blot yielded the best results (81% sensitivity).