Albumin is a family of globular, water soluble, un-glycosylated proteins commonly found in blood plasma. Albumins generally act as transport proteins that bind to various ligands to transport them around.

The most common member of this family is serum albumin. Serum albumin is produced by the liver and is the most abundant plasma protein, it provides oncotic pressure, transports bilirubin, steroids, fatty acids, thyroid hormones and other hormones, and serves as an extracellular antioxidant agent.

Too much or too little circulating serum albumin may be harmful. Perturbations in serum albumin concentration is associated with both type 2 diabetes and metabolic syndrome (MetS). Increase in serum albumin concentration might protect against early glycemic deterioration and progression to type 2 diabetes even in subjects without MetS. Albumin in the urine usually denotes the presence of kidney disease.