Background: Cytomegalovirus (CMV) infection of healthy individuals mostly
remains asymptomatic. However, infection during pregnancy bears the risk of
congenital infection. With this knowledge, the performances of the recently
approved Roche Elecsys® CMV IgG and IgM with two established CMV
assays, bioM´erieux Vidas® CMV-IgG and Medac® CMV-IgM-ELA, were
compared.
Methods: A total of 126 randomly-selected routine pregnancy samples and 50
pre-selected patient samples were investigated. Due to the absence of a gold
standard, discrepant results were resolved with avidity testing and/or research
neutralization assay.
Results: Comparison of routine pregnancy samples with Elecsys CMV IgG
and Vidas CMV-IgG found an agreement of 99.2%. In the same cohort,
comparison of IgM assays revealed an agreement of 97.62% between Elecsys
CMV IgM and Medac CMV-IgM-ELA with a specificity of 97.56% (93.04-
99.49%) and 99.10% (95.55-99.98%), respectively.
In pre-selected IgM-positives (according to Medac) with high-avidity IgG,
100% agreement was found between Elecsys CMV IgG and Vidas CMVIgG.
In contrast, comparison with IgM assays detected an agreement of 38%,
with Elecsys detecting only 19 positive/greyzone IgM of 50 Medac-positive
samples.
Conclusions: In pregnancy screening, this study shows a similar performance
of Elecsys CMV IgG and IgM to comparison assays. Elecsys CMV IgG is at
least as sensitive as Vidas. Elecsys CMV IgM shows a reasonable agreement
to Medac. In pre-selected IgM-positive/high-avidity IgG samples that might
reflect reactivated past infections, Elecsys CMV IgM detected less IgMpositive
samples which should reduce concern and follow-up screening in
routine pregnancy testing in cases with low risk of conceptus infection.