Evaluation of Toxoplasma gondii IgG and IgM assays on the new VIDIA® instrument

Department of Pathology and Laboratory Medicine, Section of Microbiology, University of Parma, Viale A. Gramsci, 14 - 43100 Parma, Italy

^* To whom correspondence should be addressed. Email: adriana.calderaro{at}unipr.it.

	Abstract

The new VIDIA® system is a fully automated system based on chemiluminescence and antigen bound to magnetic microparticles which allows a fast measurement of Toxoplasma gondii specific immunoglobulin G (IgG) and immunoglobulin M (IgM) levels. The analytical performance of the VIDIA Toxo IgG and IgM assays was evaluated in comparison with the automated VIDAS®, AxSYM® and LIAISON® Toxo IgG and IgM assays. The comparative evaluation was performed on 204 frozen sera belonging to 166 subjects and on 201 fresh sera collected from 198 subjects. For VIDIA Toxo IgG, sensitivity was 100% both in the retrospective and prospective studies and specificity was 98.39% in the retrospective and 100% in the prospective study, respectively. The sensitivity of the other three Toxo IgG assays was 100% and the specificity ranged from 96.77% to 100%. For VIDIA Toxo IgM, sensitivity and specificity were 100%, both in the retrospective and prospective studies. The overall sensitivity and specificity of the other three Toxo IgM assays ranged from 80% to 100% and from 99.44% to 100%, respectively. In our study VIDIA revealed excellent sensitivity (100% both for IgG and IgM assays) and good specificity (99.25% for IgG and 100% for IgM assay).