Preanalytical factors (biological variation) and the measurement of serum soluble intercellular adhesion molecule-I in humans: Influence of the time of day, food intake, and physical and psychological stress

Background: Adhesion proteins such as soluble intercellular adhesion molecu le-1 (sICAM-1) may be important markers for early atherosclerosis and some other diseases. To devise optimum specimen collection procedures, we invest igated the-effects on serum sICAM-1 of several preanalytical factors (facto rs that occur before a specimen is analyzed) such as the time of the day, f ood ingestion, and physical and psychological stress. Methods: Three sets of experiments were conducted: (a) 30 subjects were inv estigated during the morning, after an overnight fast, and then after the u sual breakfast and at 1200; (b) 20 subjects were studied before and after e xposure to thermal stress (sauna + swimming in ice-cold water); and (c) 15 volunteers were investigated after their driving license examination and du ring a (stress-free) control session. Conventional methods and kits were us ed to determine the blood picture and serum sICAM-1. Results: All of these preanalytical factors induced a significant increase (similar to 10%) in the concentration of sI-CAM-1. Conclusion: It is advisable to consider timing, food intake, and stress whe n collecting specimens and analyzing data on the concentration of sICAM-1 i n serum. (C) 1999 American Association for Clinical Chemistry.