This assay employs the competitive enzyme immunoassay technique. The microtiter plate provided in this kit has been pre-coated with an antibody specific to IgG. Standards or samples are then added to the appropriate microtiter plate wells with a Horseradish Peroxidase (HRP)-conjugated IgG and incubated. The competitive inhibition reaction is launched between with HRP labeled IgG and unlabeled IgG with the antibody. A substrate solution is added to the wells and the color develops in opposite to the amount of IgG in the sample. The color development is stopped and the intensity of the color is measured.