Patent ID: 7915049

Claim:
A method for determining a platelet aggregation function in blood of a patient comprising: a) flowing blood through an aperture; b) measuring a drop in pressure at the aperture as a function of time; c) measuring a blood flow volume through said aperture as a function of time; d) determining a flow resistance of the aperture based on said pressure drop and blood flow volume measurements taken in steps b) and c); e) determining a viscosity of the blood; f) calculating a hemodynamically effective radius of the aperture from said flow resistance by the Hagen-Poiseuille law; g) determining a change in said hemodynamically effective radius over time, said change being substantially linear so as to be a generally straight line having a slope (dr/dt); h) assuming a prescribed blood platelet diameter; and i) correlating the slope (dr/dt) of the substantially linear time dependent change in said hemodynamically effective radius with said blood platelet diameter to establish a platelet delay time as a measure of the rate of said platelet aggregation which provides an indication of possible risks to the patient relating to blood coagulation.