Application of the transient flow rheology to the study of abnormal human bloods

We have studied the rheological behavior in transient flow of some pathological bloods (diabetic patients and patients with polycythemia). We have used a servo-controlled Couette microviscometer, which allowed us to plot the shear stress variations as a function of time for rectangular and triangular steps of shear rates. We have compared the rheological parameters so obtained with those of the controls, and thus deduced informations about the viscoelasticity, thixotropy and shear-thinning of the different pathological blood samples.