A new capillary system was developed, incorporating infrared sensors, which
allowed the determination of whole blood viscosity over a wide range of sh
ear stresses. Flow conditions were defined by the geometry of the capillary
and the sample pressure head. Whole blood was considered to be a power law
fluid and a modified Mooney's formula was used for the calculation of the
related invariants. The new viscometer proved to be very simple in use, req
uiring one run, had a short measuring time and utilised a small test sample
volume. However it can be used for whole blood viscosity measurements only
at medium and high shear stresses.