Universal Screening with Use of Immunoglobulin G Avidity for Congenital Cytomegalovirus Infection

Abstract

Background. The aim of this prospective cohort study was to evaluate the efficacy of maternal screening for congenital cytomegalovirus infection (CCI) using cytomegalovirus (CMV) immunoglobulin G (IgG) and the IgG avidity index (AI). Methods. Pregnant women underwent screening of CMV IgG and AI measurements. IgG-negative women underwent remeasurement of IgG after educational intervention. Women with an AI ?45% received further examinations, including measurement of CMV IgM. All newborns received polymerase chain reaction analyses of the urine, and CCI was diagnosed by the detection of CMVDNA in the urine. Primary infection was defined as an AI <35% and/or positive IgM (>1.20 index). Serum samples from women with an AI >45% were stored, and the IgM levels were measured after delivery. The efficacy of AI and IgM for CCI screening was compared. Results. A total of 1562 (71.2%) women tested positive for IgG. In this study, 10 newborns with CCI were detected. The presence of infection in 3 newborns from mothers with primary infection was predicted by screening of IgG and AI <35%. However, infection in 7 newborns from women with nonprimary infection could not be predicted by screening of CMV IgG, AI <35%, or IgM. The application of an AI <35% for CCI screening yielded 22.2% sensitivity, 95.0% specificity, 2.5% positive predictive value, and 99.5% negative predictive value and was similar to that of IgM (11.1% sensitivity, 93.2% specificity, 0.9% positive predictive value, and 92.7% negative predictive value). Conclusions. Maternal screening using CMV IgG and AI can identify pregnancies with CCI from primary infection, but overlooks a number of those from nonprimary infection.