Quantification of lipid peroxidation is essential to assess the role of oxidative injury in pathophysiological disorders. Lipid peroxidation results in the formation of highly reactive, unstable hydroperoxides of both saturated and unsaturated lipids. Cayman’s Lipid Hydroperoxide Assay measures the hydroperoxides utilizing the redox reactions with ferrous ions. An easy to use quantitative extraction method is used to extract lipid hydroperoxides into chloroform and then the extract is used directly in the assay. This procedure eliminates any interference caused by H2O2 or endogenous ferric ions in the sample and provides a sensitive, reliable assay for lipid peroxidation. This kit is designed for use with either a single-tube spectrophotometer or with a 96-well microplate reader. The microplate reader requires a reusable glass plate that is supplied with the LPO Assay Kit (96 well) (Item No. 705003). The range of the assay is 0.25-5 nmol hydroperoxide per tube.