Anton Paar has published an Application Note into the use of its Lovis 2000 M/ME in the viscosity measurement of blood.
Blood viscosity is a measurement of the thickness and stickiness of an individual´s blood. It is a direct measure of the ability of blood to flow through the blood vessels. It determines how much friction the blood causes against the vessels, how hard the heart has to work to pump the blood through the body, and how much oxygen is delivered to organs and tissues. Blood viscosity is correlated with all known risk factors for cardiovascular disease - elevated blood viscosity is a strong independent predictor of cardiovascular events.
There are different kinds of testing for blood viscosity. Serum or plasma viscosity measurements have an important role in the clinical management of patients prone to hyperviscosity syndrome. But this measurement does not account for haematocrit, blood cell deformability or factors increasing RBC (red blood cell) aggregation.
Whole blood measurement is more informative, because it is affected by the hematocrit value. Nevertheless the measurements are more complex as whole blood is a non-newtonian liquid and changes its viscosity with the applied shear stress. The blood viscosity rises and falls from one extreme to the other with every cardiac cycle - much like blood pressure
The Application Note shows how the Lovis 2000 M/ME performs such analysis. The rolling-ball viscometer measures the rolling time of a ball through transparent and opaque liquids according to Hoeppler's falling ball principle. Via Peltier elements the measured solutions are brought to the desired measuring temperature extremely fast and with utmost accuracy. 3 inductive sensors measure the rolling time of a metal ball inside a capillary.