Clinical Information

Prealbumin (transthyretin or thyroxin-binding prealbumin) is synthesized in the liver and is involved in triiodothyronine (T3), thyroxine (T4), and vitamin A transport. Prealbumin is capable of binding two separate ligands at unique binding sites. Each tetrameric prealbumin molecule binds one molecule of retinol-binding protein (which complexes with vitamin A) at one site and up to two molecules of T3 or T4 at another site. Prealbumin is secondary to thyroxine-binding globulin in the transport of T3 and T4.1Because prealbumin has an extremely short half-life, quantitation of prealbumin serum levels can provide a more timely and sensitive assessment of protein malnutrition or liver dysfunction than transferrin or albumin.2Prealbumin is a very sensitive negative acute phase protein (or acute phase reactant); decreased levels are associated with inflammation, malignancy, liver cirrhosis, and protein diseases of the gut or kidneys. Prealbumin levels also fall during periods of calorie/protein malnutrition; therefore, during inflammatory processes with concomitant malnutrition, levels fall rapidly and markedly. Decreased prealbumin levels are also associated with cystic fibrosis, chronic illness, and some forms of hereditary amyloidosis.1Although the presence of acute or chronic inflammation may limit its specificity, prealbumin can be a useful marker for assessing protein-energy nutritional status of maintenance dialysis patients. In 2000, the Kidney Disease Outcomes Quality Initiative (K/DOQI) recommended a prealbumin goal of ≥ 30 mg/dL, stating, “An individual with predialysis or stabilized serum prealbumin of less than 30 mg/dL should be evaluated for protein-energy malnutrition”.3It has been reported that serum prealbumin is higher in peritoneal dialysis patients than in hemodialysis patients.4Elevated prealbumin levels are associated with high doses of corticosteroids, high levels of endogenous steroids secondary to adrenal hyperactivity, high doses of nonsteroidal anti-inflammatory medication, and Hodgkin’s disease.