A serological testing algorithm for the diagnosis of primary CMV infection in pregnant women

Abstract

Serological diagnosis of CMV primary infection is usually based on the detection of specific IgM antibody. However, as the presence of IgM antibody is not always correlated with primary infection, measurement of IgG avidity must be performed. The aim of our study was to evaluate the best procedure for serological diagnosis of CMV primary infection. In other words, is it better to first search for IgM antibody, and, if positive, then measure IgG avidity, or first measure IgG avidity without the detection of IgM antibody? CMV-IgM detection and CMV-IgG avidity measurement were performed on 310 IgG positive sera from pregnant women. CMV-IgM antibody was detected positive for 9 of 310 sera. Using CMV-IgG avidity index (AI), dating of infection was difficult in 81/310 cases (26%), while it failed in only 3/310 cases using CMV-IgM plus CMV-IgG AI. The diagnosis of primary CMV infection can be based on the detection of CMV-IgM antibody first and then on the measurement of CMV-IgG AI.