Blood Coagulation Meter: A Low Cost Viscoelasticity based Approach

Blood coagulation is an essential defense mechanism of the human body. In case of injury, it prevents excessive blood loss and reduces the chances of infection. In conditions like Hemophilia and von Willebrand´s disease, clotting is insufficient. The coagulation process depends on certain clotting factors as well as the platelet count. A coagulometer is a device that measures the rate of coagulation of blood. The ones available in the market today are expensive and not affordable to the smaller hospitals and labs. We propose an alternative, innovative and economical design to make a device that can measure the rate and extent of coagulation. Our principle is that the conduction of vibrations is directly related to increasing viscosity. The basic mechanism of our device is passing mechanical waves through a column of blood and detecting the response using a piezofilm, which converts pressure into a voltage signal. As blood coagulates, its viscosity increases and thereby, the amplitude of the signal that is detected also increases with time. Once all the blood clots, the amplitude of the output should remain relatively constant. Upon performing analysis on the thromboelastogram obtained, certain significant parameters such as the envelope and the slope can be determined.