The usefulness of cytomegalovirus IgG avidity tests for predicting congenital cytomegalovirus infection: A comparison between chemiluminescent microparticle immunoassay and enzyme-linked immunosorbent assay.

INTRODUCTION

This study evaluated the correlation between cytomegalovirus (CMV) IgG avidity measured by chemiluminescent microparticle immunoassay (CMIA) and enzyme-linked immunosorbent assay (ELISA), and assessed the usefulness of CMIA for predicting congenital CMV (cCMV) infection, compared with ELISA.

METHODS

A total of 130 serum samples, previously tested for CMV IgG avidity using ELISA, were selected. Thirty samples were obtained from pregnant women positive for both CMV-specific IgG (CMV IgG) and IgM, and 100 samples were obtained from pregnant women positive for CMV IgG but negative for CMV IgM. CMV IgG avidities in these stored sera were measured by CMIA and compared with the ELISA results.

RESULTS

A strong positive correlation was observed between CMV IgG avidities measured by ELISA and CMIA among the 30 pregnant women positive for both CMV IgG and IgM (Spearman's ρ = 0.78, p = 3.8 × 10-7). Additionally, in 121 women (93.1%), the CMIA classifications of low and high avidities (low: <50%Avi, high: ≥60%Avi) were consistent with those from ELISA (low: <35%, high: >40%). Among the 18 pregnant women whose newborns had cCMV infection, eight and six were classified as having low avidities by ELISA and CMIA, respectively.

CONCLUSIONS

The high concordance rate in classifying CMV IgG avidities as low or high between ELISA and CMIA suggests that both methods exhibit similar clinical usefulness in predicting cCMV infection resulting from primary maternal CMV infection.