Cayman’s PC Assay provides a specific, sensitive, and convenient method for quantifying PC in plasma or serum. In this assay, PC-Specific PLD hydrolyzes PC to choline and phosphatidic acid. The newly formed choline is then used to generate hydrogen peroxide in a reaction catalyzed by choline oxidase. Finally, with peroxidase as a catalyst, hydrogen peroxide reacts with DAOS and 4-aminoantipyrine to generate a blue dye with an optimal absorption at 595 nm.