The influence of hematocrit on the viscoelasticity of human blood is examined in two contexts. First, the viscosity and elasticity vs shear rate is determined at 2 Hertz using blood from a single donor, reconstituted at hematocrits ranging from 0 to .95. The viscosity changes approximately exponentially with hematocrit for both low shear rates,
< 1 sec−1 , and at higher shear rates,
= 10 sec−1. For hematocrits near .45, both viscosity and elasticity changes are well described by a power curve, viscosity being near the second and elasticity being near the third power of hematocrit. Second, statistical analysis of a group of normal male donors shows a similar power curve dependence on hematocrit. A procedure for compensation for hematocrit differences among donors is described. It is applied to obtain normal values for viscosity and elasticity at two shear rates for the group. Under the conditions of testing and for a hematocrit of .45, the mean values for viscosity at 1 and 10 −1 are .114P and .085P, respectively, while the corresponding elasticities are .045P and .019P.
