Preanalytical Factors (Biological Variation) and the Measurement of Serum Soluble Intercellular Adhesion Molecule-1 in Humans: Influence of the Time of Day, Food Intake, And Physical and Psychological Stress (General Clinical Chemistry‪)‬

Intercellular adhesion molecule-1 (ICAM-1) [1] is a widely distributed adhesion factor present on the surfaces of endothelial cells and leukocytes. This protein mediates adhesion and transmigration of leukocytes through the endothelium. Surface expressed ICAM-1 is apparently shed from the cells and then circulates as soluble ICAM-1 (sICAM-1). A recent study demonstrated that subjects with basal plasma concentrations of sICAM-1 in the top quartile of the health-related reference interval have an 80% higher risk of developing myocardial infarction than those with concentrations in the lowest quartile (1). Although exercise has a beneficial effect on cardiovascular morbidity, it may increase the concentrations of sICAM-1 (2-4). Because this analyte may become of importance in routine laboratory testing, it is important to collect information about its biological variation and about the effects of preanalytical factors that may influence the result of the assay. In the present study, we investigated the effects of several preanalytical factors: food intake, time of the day, and physical and psychological stress. In addition, we calculated different kinds of indices related to biological variation. Finally, the results were considered against the background of population-based health-related reference values.