Albumin is one of the major products of hepatic protein synthesis. Although it is a small molecule, it is an important diagnostic and prognostic determinant, as well as a useful therapeutic agent. A review of the evolution and structure of albumin as well as a description of its colloidal and buffering properties is presented. Synthesis, distribution, and catabolism, the major determinants of serum albumin level, are discussed. Emphasis is given to those mechanisms responsible for the regulation of these processes, including the importance of nutritional status on substrate availability, energy supply, and hormonal modulation.

The serum albumin level is one of several clinical parameters of the status of general health. There is a marked correlation between low albumin levels and the incidence of morbidity and mortality in hospitalized patients. Therefore, it is not surprising to find that hypoalbuminemia is a common finding among hospitalized patients. This results from alterations in the catabolic or anabolic rates, losses of albumin, or redistribution between the various fluid compartments of the body. Somewhat less well defined than the role of albumin as a prognostic indicator is its role in compounding pathophysiology. Hypoalbuminemia is known to be associated with delayed wound healing. The hypoalbuminemic state interferes with the normal functioning of the gastrointestinal tract. Qualitative changes in the albumin molecule which occur in renal disease may damage the nephron. Low serum albumin levels may adversely affect the coagulation system. Further investigation into the role of albumin in pathophysiology is warranted.

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