Cardiovascular disease is the major cause of mortality globally. The role of platelets and antiplatelet drugs in the treatment of cardiovascular disease is widely appreciated. Platelets have a less well-known role in cancer and inflammation and as the role of platelets in cancer and inflammation is increasingly understood, there is a compelling need to develop diagnostic assays of platelet function to guide clinical management. Most current platelet-function tests are focused on platelet aggregation, are cumbersome, require dedicated laboratory personnel, measure a single response to a single agonist and artificially separate platelets from blood, thus, these assays do not reflect the pathophysiolgical environment of complex disease states. New technology platforms are emerging that address the physiological adhesive function of platelets to vascular-specific matrices using small volumes of whole blood, giving rapid results. These technologies will guide therapy in the prevention of cardiovascular disease and probably in risk management in both cancer and atherosclerosis.