Abstract: A method of generating a platelet reactivity profile of an individual comprises the steps of providing a platelet-containing biological sample from the individual, providing at least three platelet function modulators, each platelet function modulator being provided in at least three concentrations, and reacting an aliquot of the platelet containing sample with each concentration of each platelet function modulator in a separate reaction vessel. Platelet aggregation is then measured in each reaction vessel, and the platelet aggregation measurements are used to generate a dose response curve for each platelet function modulator, wherein the dose response curves obtained and/or one or more functions of the dose response curves obtained, comprise a platelet reactivity profile for the individual. Clinical applications of, and kits for carrying out, the methods of the invention are also described.