The clinical evaluation of plasma fibronectin as a marker for nutritional depletion and repletion and as a measure of nitrogen balance.

Plasma fibronectin has been suggested as a possible marker for nutritional repletion or depletion. This study was undertaken to evaluate the usefulness of plasma fibronectin in patients who received intense nutritional support. Twenty-seven patients referred to our Nutritional Support Services were followed for 3 to 5 wk; 22 received parenteral hyperalimentation alone, two received enteral alone, and three received a combination of both. Plasma fibronectin, serum albumin, serum transferrin, total lymphocyte counts, and 24-hr urine nitrogen balance studies were performed weekly; anthropometric measurements were performed every other week. Plasma fibronectin concentration, measured by laser nephelometry, showed a significant rise (p less than 0.005) in all patients after 1 wk of nutritional therapy; however, there was no significant difference among the subsequent weeks. Plasma fibronectin did not correlate with nitrogen balance studies, serum albumin, or total lymphocyte counts. A correlation between serum transferrin and plasma fibronectin was found not to be clinically useful. Thus, plasma fibronectin is sensitive to nutritional repletion after 1 wk of therapy, but is not useful thereafter. The relationship among nutritional status, immunologic function, plasma fibronectin, and other serum proteins are discussed.