For many years clinicians have relied on serum proteins, such as albumin and pre-albumin, as markers of nutritional status. However, current research indicates that there is little data to support this practice. Albumin and pre-albumin (transthyretin) are acute phase proteins. The advent of the inflammatory process - including infection, trauma, surgery, burns, and other wounds - elicits the acute phase response. During this acute phase response, these proteins decline and are called negative acute phase reactants.
Albumin is a visceral protein and has a large body pool, distributed between the vascular and interstitial spaces. Only 5 % is synthesized daily. Albumin functions as a carrier protein, and assists in maintaining oncotic pressure. Corticosteroids, insulin, thyroid hormone, and dehydration all increase albumin levels. During inflammation, cytokines increase, especially interleukin-6, which is responsible for the production of acute phase proteins. This increased cytokine production results in albumin being pulled from the intravascular spaces and circulating to the liver until the inflammatory process resolves