The DRG Toxoplasma gondii IgA Enzyme Immunoassay Kit provides materials for the qualitative and semi quantitative determination of IgA-class antibodies to Toxoplasma gondii in human serum and plasma (EDTA- or heparin plasma). This product is for Research Use Only; International customers contact your representative to receive information about the CE marked version. The DRG Toxoplasma gondii IgA ELISA Kit is a solid phase enzyme-linked immunosorbent assay (ELISA). Samples are diluted with Sample Diluent and additionally incubated with IgG-RF-Sorbent to eliminate competitive inhibition from specific IgG. This pretreatment avoids false negative results. Microtiter wells as a solid phase are coated with inactivated Toxoplasma gondii soluble antigen (strain RH). Diluted specimens and ready-for-use controls are pipetted into these wells. During incubation Toxoplasma gondii-specific antibodies of positive specimens and controls are bound to the immobilized antigens. After a washing step to remove unbound sample and control material horseradish peroxidase conjugated anti-human IgA antibodies are dispensed into the wells. During a second incubation this anti IgA conjugate binds specifically to IgA antibodies resulting in the formation of enzyme-linked immune complexes. After a second washing step to remove unbound conjugate the immune complexes formed (in case of positive results) are detected by incubation with TMB substrate and development of a blue color. The blue color turns into yellow by stopping the enzymatic indicator reaction with sulfuric acid. The intensity of this color is directly proportional to the amount of Toxoplasma gondii-specific IgA antibody in the specimen. Absorbance at 450 nm is read using an ELISA microtiter plate reader.