Coenzyme Q10 (CoQ10) plays an outstanding role in the energy production within the cell metabolism. In addition, CoQ10 is an important antioxidant and thus protects the cell from radical oxidation (oxidative stress). Lowered blood concentrations of CoQ10 seem to be connected with the pathogenesis of a large number of diseases. On the other hand, CoQ10 deficiencies are known to be the result of a pathological condition, such as in cardiomyophathies. There, a deficient CoQ10 status may be impaired by therapy with certain lipid-lowering agents (statins) and thus requires monitoring of the CoQ10 level. The RECIPE test kit provides reliable determination of CoQ10 in whole blood, plasma and serum. For quality assurance of the analytical results reference materials (Test Solution, Plasma Calibrator and Plasma Controls) with excellent stability are available.