Plasma leucine

There are 21 amino acids that make up human proteins. Normal human plasma amino acid concentration fluctuates diurnally, generally peaking between 8 and 10 am in the morning and trough at midnight. The determination of amino acids and their products is of great significance for the diagnosis of congenital or acquired metabolic diseases. Leucine in serum or plasma is measured clinically. To avoid the effects of food digestion and absorption, blood should be collected on an empty stomach in the early morning.