The redox status of mitochondrial coenzyme Q (CoQ) is an important marker for oxidative stress associated with several disorders such as Parkinson disease and Alzheimer disease. Altered redox status may be present in mitochondrial electron transport complex disorders. Intracellular CoQ levels reflect the functional status of the mitochondrial electron transport complex better than plasma levels. Here, we describe the method to determine the reduced and oxidized form of CoQ in white blood cells using LC–MS/MS.
