Evaluation of the new architect cytomegalovirus immunoglobulin M (IgM), IgG, and IgG avidity assays.

A panel of new cytomegalovirus (CMV) assays for use on the Architect instrument has been developed, including a CMV avidity assay based on a new technology. The purpose of this study was to compare the performance characteristics of the fully automated CMV immunoglobulin M (IgM), IgG, and IgG avidity tests on the Architect instrument with those of other available assays. A total of 503 consecutive fresh patient serum specimens (routine serum specimens) and 96 serum specimens from 33 pregnant women with a recent CMV primary infection (seroconversion serum specimens) were tested for CMV IgM and IgG by the Architect (Abbott), Vidas (BioMérieux), and Enzygnost (Siemens) assays. The seroconversion sera and 100 preselected serum specimens IgM negative and IgG positive by the AxSYM assay were also tested by the IgG avidity tests on the Architect and Vidas instruments. The relative agreements for CMV IgM determination with routine sera between the Architect assay and the Vidas, Enzygnost, and AxSYM assays were 97%, 94%, and 93%, respectively, for the CMV IgM tests and 99%, 98%, and 98%, respectively, for the CMV IgG tests. The specificities of the CMV IgG avidity test were 98% for the Architect assay and 76% for the Vidas assay. No high CMV IgG avidity test results were found within the first 3 months after seroconversion by either of those assays. The correlation between the results of the newly developed CMV IgM and IgG tests on the Architect instrument with the Vidas and Enzygnost assays was excellent (> or = 94%). The CMV IgG avidity test reliably excluded patients with recent infections and showed an excellent specificity (98%).