title: European multicenter study of the LIAISON automated diagnostic system for determination of Toxoplasma gondii-specific immunoglobulin G (IgG) and IgM and the IgG avidity index.
abstract: The LIAISON system is a fully automated system based on chemiluminescence and antigen bound to magnetic microparticles. The system allows fast and precise measurement of Toxoplasma-specific immunoglobulin G (IgG) and IgM antibody levels and measurement of the IgG avidity index even at low levels of Toxoplasma-specific IgG antibodies in a single step without manual interference. Seven European centers participated in a multicenter evaluation of the LIAISON system. The sensitivity and specificity of the LIAISON system compared to the Sabin-Feldman dye test were 99.3 and 96.8%, respectively. In a comparison of the LIAISON Toxoplasma-specific IgM assay with an immunosorbent agglutination assay, the LIAISON assay had a sensitivity of 96.7% and a specificity of 95.4%. The LIAISON IgG assay showed agreements of 91, 100, and 100% with the AXSYM IgG (Abbott), VIDAS IgG (bioMerieux), and Platelia IgG (Bio-Rad) assays, respectively. The LIAISON IgM assay showed agreements of 95% with the AXSYM IgM and Platelia IgM assays, 96% with the ISAGA IgM assay (bioMerieux), and 97% with the VIDAS IgM assay. The coefficient of correlation between the LIAISON system and the VIDAS Toxoplasma-specific IgG avidity index was 0.81. By use of the Toxoplasma-specific IgG avidity index assay with specific IgM-positive samples, the diagnosis of infection with Toxoplasma gondii in early pregnancy has been improved significantly. The LIAISON avidity assay is a valuable assay for the exclusion of recently acquired infection with T. gondii (less than 4 months) in pregnant women, and it decreases significantly the necessity for follow-up testing.
authors.affiliation: WHO/FAO International Centre for Research and Reference on Toxoplasmosis, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark. eskildp@dadlnet.dk
authors.forename: Eskild
authors.initials: E
authors.lastname: Petersen
authors.forename: Maria Victoria
authors.initials: MV
authors.lastname: Borobio
authors.forename: Edward
authors.initials: E
authors.lastname: Guy
authors.forename: Oliver
authors.initials: O
authors.lastname: Liesenfeld
authors.forename: Valeria
authors.initials: V
authors.lastname: Meroni
authors.forename: Anne
authors.initials: A
authors.lastname: Naessens
authors.forename: Emma
authors.initials: E
authors.lastname: Spranzi
authors.forename: Philippe
authors.initials: P
authors.lastname: Thulliez
mesh_terms: D000818:Animals; D000915:Antibody Affinity; D001331:Automation; D005060:Europe; D005260:Female; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D007075:Immunoglobulin M / Q000097:blood*; D007231:Infant, Newborn; D007753:Laboratories; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000175:diagnosis / Q000469:parasitology; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000469:parasitology; D014125:Toxoplasmosis, Congenital / Q000175:diagnosis / Q000469:parasitology
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011933:Reagent Kits, Diagnostic