This method for the determination of total cholesterol in serum is based on the use of three enzymes: cholesterol esterase (CE), cholesterol oxidase (CO), and peroxidase (POD). In the presence of the latter, the mixture of phenol and 4-aminoantipyrine (4-AA) condenses due to hydrogen peroxide, forming a colored quinonimine proportional to the concentration of cholesterol in the sample.
