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

Abstract

Background: Adhesion proteins such as soluble intercellular adhesion molecule-1 (sICAM-1) may be important markers for early atherosclerosis and some other diseases. To devise optimum specimen collection procedures, we investigated the effects on serum sICAM-1 of several preanalytical factors (factors that occur before a specimen is analyzed) such as the time of the day, food ingestion, and physical and psychological stress. Methods: Three sets of experiments were conducted: (a) 30 subjects were investigated during the morning, after an overnight fast, and then after the usual breakfast and at 1200; (b) 20 subjects were studied before and after exposure to thermal stress (sauna + swimming in ice-cold water); and (c) 15 volunteers were investigated after their driving license examination and during a (stress- free) control session. Conventional methods and kits were used to determine the blood picture and serum sICAM-1. Results: All of these preanalytical factors induced a significant increase (~10%) in the concentration of sICAM- 1. Conclusion: It is advisable to consider timing, food intake, and stress when collecting specimens and analyzing data on the concentration of sICAM-1 in serum.