Cayman’s Glucose Assay provides a simple, reproducible, and sensitive tool for assaying glucose in plasma, serum, and urine. The glucose assay uses the glucose oxidase-peroxide reaction for the determination of glucose concentrations. In this assay, glucose is oxidized to d-gluconolactone with concomitant reduction of the flavin adenine dinucleotide (FAD)-dependent enzyme glucose oxidase. The reduced form of glucose oxidase is regenerated to its oxidized form by molecular oxygen to produce hydrogen peroxide. Finally, with horseradish peroxidase as a catalyst, hydrogen peroxide reacts with 3,5-dichloro-2-hydroxybenzenesulfonic acid and 4-aminoantipyrine to generate a pink dye with an optimal absorption at 514 nm.