Albumin is a globular, unglycosylated protein produced in the liver. It is the most abundant protein in the blood plasma, constituting about half of all proteins in the plasma. The main function of albumin is to act as a carrier protein for steroids, hormones, fatty acids, and other compounds, and as a regulator of the colloidal osmotic pressure of the blood.
Normal serum albumin in the plasma ranges from 3.4-5.4 g/dL. Abnormal levels may be an indication for renal or hepatic diseases. Albumin dysfunction is also responsible for an autosomal dominant condition called familial dysalbuminemic hyperthyroxinemia (FDH). FDH is characterized by increased circulating total thyroxine concentrations (T4) and normal physiological thyroid function.