Shear dependence of blood coagulation

Abstract

Although blood clotting is often referred to as shear dependent, there are little experimental data to support this. In a set of experiments fresh, non-anticoagulated blood was submitted to Couette flow. All surfaces in contact with blood had been siliconized. Samples were tested at three different shear rates i.e. shear stresses covering the physiological range. In each case clotting was detected by a 10% change of the otherwise constant reading in the x–y recorder. The results indicate a shear dependence of clotting time which decreases as shear increases.