Laboratory monitoring of nutritional status in burn patients

Most nutrition laboratory testing relies on serum concentrations of ingested nutrients, their coenzymes, proteins, or lipids. Alternatively, functional tests measure a specific physiological process or biochemical reaction. We compared these two approaches to nutritional assessment in intensive-care burn patients, in whom the serum concentrations of transthyretin (prealbumin), albumin, transferrin, carotene, retinol, ascorbic acid, copper, cholesterol, iron, and calcium were all below established reference ranges. In contrast, serum triglyceride concentrations were often above the reference range. Functional tests for thiamin, riboflavin, pyridoxine, and iron (by zinc protoporphyrin/heme ratio) in these patients all showed normal values. Dietary intake, weight trends, and nitrogen balances all indicated that these patients' estimated caloric and protein needs had been met. These findings suggest that static measurements of serum concentrations may be unreliable indicators of nutritional status in burn patients.