Elevation of blood viscosity produced by shearing in a rotational viscometer and its inhibition by refrigeration 1

Abstract

Rotational viscometers have become important tools for measurement of blood viscosity. The present data reveal a potential source of error in such measurements, namely an elevation in viscosity produced by shearing in the viscometer. The viscosity of mouse blood and of human blood was measured in a GDM viscometer over a range of 300–0.3 sec⁻¹. When the same aliquot of blood was used for a subsequent series of viscosity measurements, it was found that viscosity had risen, uniformly with mouse blood, and occasionally with human blood. A lag period was present before the rise in viscosity appeared. Subsequent series of measurements then revealed further increments in viscosity values until a plateau was reached. Refrigeration prior to any shearing, prevented the shear-dependent rise in viscosity. Results are interpreted in terms of possible damage to cells in the viscometer, producing a rise in blood viscosity, or resulting in release of some constituent of the cell which would in turn elevate blood viscosity.