Method Description

The electrochemiluminescence immunoassay for the in vitro qualitative determination of IgM antibodies to Toxoplasma gondii in human serum is a micro-capture test principle. During the first incubation, 6 mcL of sample are automatically prediluted 1:20 with Diluent Universal. T gondii-specific recombinant antigen labeled with a ruthenium complexa is added. Anti-Toxo IgM antibodies present in the sample react with the ruthenium-labeled T gondii-specific recombinant antigen. In the second incubation, biotinylated monoclonal h-IgM-specific antibodies and streptavidin-coated microparticles are added. The complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier. Results are determined automatically by the software by comparing the electrochemiluminescence signal obtained from the reaction product of the sample with the signal of the cutoff value previously obtained by calibration.(Package insert: Elecsys Toxo IgM, Roche Diagnostics. GmbH, 01/2024)

The electrochemiluminescence immunoassay for the in vitro quantitative determination of IgG antibodies to Toxoplasma gondii in human serum is a sandwich test principle. During the first incubation, 6 mcL of sample a biotinylated recombinant T gondii-specific antigen labeled with a ruthenium complex form a sandwich complex. In the second incubation, streptavidin-coated microparticles are added and the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier. Results are determined by a calibration curve which is instrument-specifically generated by 2-point calibration and a master curve provided via the cobas link.(Package insert: Elecsys Toxo IgG, Roche Diagnostics. GmbH, 02/2022)