Endothelial cells control the balance between a number of opposing biological processes. Injury to these cells leads to a shift in this delicate balance; the resultant endothelial dysfunction ultimately leads to atherosclerotic disease. Specific markers of endothelial dysfunction can be used to detect and monitor the progression of atherosclerosis; they can also be used to study the pathogenesis of disease. Specific markers may be indicative of a particular stage in the pathogenesis of disease. By using a rigorous screening process, various markers of endothelial dysfunction can be identified. Common markers of endothelial dysfunction that are used in clinical studies are vascular cell adhesion molecule-1, intracellular adhesion molecule-1 and fibrinogen.