Quantitative analytical methods that show antigen-antibody reactions through the color change obtained by using an enzyme-linked conjugate and enzyme substrate and that serve to identify the presence and concentration of molecules in biological fluids are generally called enzyme immunotests, enzyme-linked immunosorbent assay (ELISA). This method can be used to measure even substances in very low concentrations with hardly any risk of interference. When we have the antigen which we know to be specific to a certain substance, we can identify the type and amount of its antibody and when we have the antibody, we can find out its specific antigen and the amount of antigen, using this method