Evaluation of Rubella IgG and IgM assays on the new Vidia® instrument

Abstract number: 1734_108

Medici M.C., Albonetti V., Martinelli M., Chezzi C., Dettori G.

Objective: The aim of the present study was to evaluate the performance of the new VIDIA® Rubella IgG and IgM assays on the fully automated VIDIA instrument, easy to use with a high level of traceability.

Methods: Sensitivity and specificity of the VIDIA RUB IgG and IgM (bioMérieux, France) were evaluated in a retrospective study on 209 serum samples belonging to 195 subjects and in a prospective study on 211 serum samples belonging to 210 subjects, in comparison with VIDAS® RUB IgG and IgM (bioMérieux, France), AxSYM® Rubella IgG and IgM (Abbott, USA) and LIAISON® Rubella IgG and IgM (DiaSorin, Italy) assays.

The samples for which at least one equivocal result have been found whatever the method have been excluded for the analysis, as well as the non resolved samples.

Discrepancies were resolved considering individual clinical data, when available, and/or with repetition of the test as well as with IgG Avidity test for IgM discrepancies.

Results: Sensitivity: For VIDIA RUB IgG, sensitivity was 100% in comparison with 2 out of 3 methods in the retrospective study and with all methods in the prospective one. For VIDIA RUB IgM, in the retrospective study, sensitivity was 100% only in comparison with VIDAS RUB IgM. After resolution of discrepancies, the absolute sensitivity was 100% for all methods except AxSYM Rubella IgM which was 33.33%. In the prospective study the sensitivity was not determinable as no positive serum was obtained.

Specificity: For VIDIA RUB IgG, the specificity has been established at 100% compared to VIDAS RUB IgG and AxSYM Rubella IgG in both retrospective and prospective studies. In comparison with LIAISON Rubella IgG it was 97.29% and 95.24% in the retrospective and prospective studies, respectively. After resolution of discrepancies the absolute sensitivity was found 100%.

The relative specificity of VIDIA RUB IgM compared to VIDAS RUB IgM, AxSYM Rubella IgM and LIAISON Rubella IgM assays was 99.49%, 98.44 and 99.47, respectively, in the retrospective study. Taking into account clinical information and Avidity results, the absolute specificity was closed to 100%. In the prospective study the specificity of VIDIA RUB IgM was found 100% for all the three methods.

Conclusion: The two evaluated assays, VIDIA RUB IgG and VIDIA RUB IgM, show an excellent sensitivity and specificity.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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