Serum albumin, generally referred to as human blood albumin, is a protein composed of single chains of 580 amino acid residues and is secreted by the liver, with the highest content in plasma, accounting for about 52%-68%. Plasma albumin plays an important physiological role in the body, including the role of transport and the binding of various substances in the body to form an important buffer. The normal reference value of serum albumin is 20-40g/L. Elevated serum albumin actually as a physical examination is usually falsely elevated and is commonly associated with concentrated dehydration and profuse sweating. If the day before the physical examination is not carried out to drink water, or cause the body concentrated resulting in a false increase in serum albumin. Decreased serum albumin is seen in a variety of diseases, such as hepatitis, kidney disease, malnutrition, etc. If albumin is <20g/L it can cause swelling.