AMS Biotechnology has introduced the MitoXpress Xtra Fatty Acid Oxidation (FAO) kit to facilitate convenient measurement of FAO-driven respiration. FAO is the primary metabolic pathway in a variety of tissues, and is particularly important during periods of glucose deprivation. In tissues such as liver and skeletal muscle, FAO can provide over 75% of cellular adenosine triphosphate, while in cardiac tissue it can be responsible for up to 90%. It is also acknowledged as a key factor in cancer metabolism and drug-induced microsteatosis. The MitoXpress Xtra FAO kit is designed for use with the MitoXpress Xtra HS–Oxygen Consumption Assay, and contains the 18-carbon unsaturated fatty acid oleate as substrate, supplied as a 2:1 bovine serum albumin conjugate. The kit also contains a buffer tablet and L-carnitine for convenient preparation of measurement media, and two FAO modulators, etomoxir and FCCP.