The Denka Direct LDL assay accurately measures low-density lipoproteins (LDL) in the specimen using a two step procedure based on patented technology. In the first step, non-LDL lipoproteins, including chylomicrons, VLDL, IDL and HDL, are decomposed by cholesterol esterase and cholesterol oxidase. The hydrogen peroxides produced are finally decomposed by the action of catalase. In the second step, an LDL-specific surfactant is used to release the cholesterol and similar enzymatic degradation in the presence of peroxidase to produce a measurable purple-red color on any clinical chemistry analyzer.