Glycerol is the backbone of triglycerides and an important intermediate in energy metabolism being involved in both oxidative and synthetic processes. The circulating levels of glycerol and free fatty acids are considered to reflect lipolysis and are therefore useful parameters to evaluate in various conditions. The measurement of glycerol is also useful for correction of glycerol interference when measuring triglycerides in reference materials and in serum from patients with elevated glycerol concentrations. Cayman’s Glycerol Assay provides a simple, reproducible, and sensitive tool for measurement of glycerol in plasma and serum. The assay employs a coupled enzymatic reaction system that yields a brilliant purple product with an absorbance maximum at 540 nm.