What is "serum albumin"

Serum \Se"rum\ (s[=e]"r[u^]m), n. [L., akin to Gr. ???, Skr. s[=a]ra curd.] (Physiol.)

1. The watery portion of certain animal fluids, as blood, milk, etc.

2. A thin watery fluid, containing more or less albumin, secreted by the serous membranes of the body, such as the pericardium and peritoneum.

   Blood serum, the pale yellowish fluid which exudes from the clot formed in the coagulation of the blood; the liquid portion of the blood, after removal of the blood corpuscles and the fibrin.

   Muscle serum, the thin watery fluid which separates from the muscles after coagulation of the muscle plasma; the watery portion of the plasma. See Muscle plasma, under Plasma.

   Serum albumin (Physiol. Chem.), an albuminous body, closely related to egg albumin, present in nearly all serous fluids; esp., the albumin of blood serum.

   Serum globulin (Physiol. Chem.), paraglobulin.

   Serum of milk (Physiol. Chem.), the whey, or fluid portion of milk, remaining after removal of the casein and fat.

n. albumin occurring in blood serum; serves to maintain the somatic pressure of the blood

Serum albumin, often referred to simply as blood albumin, is an albumin (a type of globular protein) found in vertebrate blood. Human serum albumin is encoded by the ALB gene. Other mammalian forms, such as bovine serum albumin, are chemically similar.

Serum albumin is produced by the liver, occurs dissolved in blood plasma and is the most abundant blood protein in mammals. Albumin is essential for maintaining the oncotic pressure needed for proper distribution of body fluids between blood vessels and body tissues; without albumin, the high pressure in the blood vessels would force more fluids out into the tissues. It also acts as a plasma carrier by non-specifically binding several hydrophobic steroid hormones and as a transport protein for hemin and fatty acids. Too much or too little circulating serum albumin may be harmful. Albumin in the urine usually denotes the presence of kidney disease. Occasionally albumin appears in the urine of normal persons following long standing ( postural albuminuria).