Blood Coagulation Time Determination by AC Current Phase Shift Measurement

The phase shift of the AC current resulting from the applied AC potential is one of the important parameters determining the shape of the registered curve in the EIS studies. However, its self-sufficient employment is limited while the Nyquist and Bode diagrams are widely applied in the common EIS analysis so far. In this work a new approach was proposed, tested and applied for rapid and precise blood coagulation time determination, a parameter of a great importance for the diagnosis and monitoring of many diseases. The proposed approach is based on AC current phase shift measurement in respect to the applied AC potential with small amplitude as a self-sufficient blood properties characterizing parameter. A specially developed LabVIEW based virtual instrument was used providing results which relative RSD does not exceed 1.9% in the frequency range from 100 Hz up to 10 KHz.