Clinical microbiology and infection vol:vol. 14 pages:S1-S815
European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) edition:18th location:Barcelona, Spain date:April 19-22th 2008
Objectives: A panel of new CMV assays for 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 of the fully automated CMV IgM, IgG and IgG avidity tests on ARCHITECT with other available assays.
Methods: 503 consecutive fresh patient sera (routine sera) received at the University Hospital laboratory for CMV IgM and IgG testing on AxSYM (Abbott), 100 preselected AxSYM IgM positive sera and 96 sera from 33 pregnant women with a recent CMV primo infection (seroconversion sera) were tested for CMV IgM and IgG on the ARHCITECT (Abbott), VIDAS (BioMerieux) and Dade Behring assays. The seroconversion sera were also tested with the IgG avidity tests developed on ARCHITECT and VIDAS. The specificity of the avidity tests was assessed on 100 preselected AxSYM IgM negative, IgG positive sera.
Results: The relative agreement for the CMV IgM determination on the routine sera between ARCHITECT and VIDAS, Dade Behring and AxSYM was respectively 97%, 94% and 93% for the CMV IgM tests and 99%, 98% and 98% for the CMV IgG tests. CMV IgM reactivity on ARCHITECT but not with the other assays, occurred only in 1 of the 503 routine sera (0.2%). In 3.0% of routine sera CMV IgM was positive only on AxSYM. CMV IgG avidity was high in 50% of routine sera with ARCHITECT CMV IgM reactivity. All preselected AxSYM IgM positive sera with a low VIDAS IgG avidity were reactive on all IgM assays tested. The specificity of the CMV IgG avidity test was 98% for ARCHITECT and 76% for VIDAS. No high CMV IgG avidity test results were found within the first 3 months after seroconversion with both assays. High avidity was attained earlier on ARCHITECT than on VIDAS. In several patients no gradual increase in avidity was observed after seroconversion. This phenomenon was more frequent with the ARCHITECT avidity test compared to the VIDAS assay. The increase in the avidity values after seroconversion needs further validation.
Conclusion: The correlation between the newly developed CMV IgM and IgG tests on ARCHITECT with the VIDAS and Dade Behring assays was excellent (>= 94%) and was highest between ARCHITECT and VIDAS. The CMV IgG avidity test reliably excluded recent infections and showed an excellent specificity (98%).