Monkey Cardiac FABP (for serum) Fatty acid-binding proteins (FABP) are cytosolic proteins of about 15 kDa. They bind long chain fatty acids and play an important role in fatty acid metabolism. Heart, liver, and intestinal FABP isoforms exist. Heart has a high content of FABP (10-20 mol % of cytoplasmic proteins), and heart FABP (H-FABP) has proved to be a sensitive biomarker of myocardial necrosis in humans. H-FABP is rapidly released into the circulation from damaged cardiac muscle. In humans serum levels increase significantly within 1-4 hours of muscle injury and return to normal within 12 to 24 hours. Because H-FABP is also expressed in skeletal muscle, it is necessary to exclude or control for skeletal muscle injury before ascribing H-FABP elevations to cardiac injury. However, in the absence of cardiac injury H-FABP is a useful biomarker of skeletal muscle injury. Validation studies at Life Diagnostics Inc., revealed basal monkey H-FABP levels of ~ 20 ng/ml with levels in excess of 400 ng/ml in animals with muscle injury.