Profile: Cortez Diagnostics, Inc. specializes in providing Elisa kits and IFA kits. Diagnostic automation Elisa kit is designed to detect IgG class antibodies to a variety of common nuclear antigens in human sera. Wells of plastic microwell strips are sensitized by passive absorption with antigen. The test procedure involves three incubation steps such as the properly diluted test sera are incubated in antigen coated microwells. Any antigen specific antibody in the sample will bind to the immobilized antigen. Afterwards the plate is washed to remove unbound antibody and other serum components. The peroxidase conjugated goat anti-human IgG is added to the wells and the plate is incubated. The conjugate will react with the antibody immobilized on the solid phase. The wells are washed to remove unreacted conjugate. Microwells containing immobilized peroxidase conjugate are incubated with peroxidase substrate solution. The hydrolysis of the substrate by peroxidase produces a color change. After a period of time the reaction is stopped and the color intensity of the solution is measured photometrically. The color intensity of the solution depends upon the antibody concentration in the original test sample.