It was observed that in the range of 60.16% and 25.32%, a 10.99% increase of hematocrit produced an increase of 1 unit relative viscosity, which means approximately a 20% increase in blood viscosity for a healthy individual. The results were evaluated by the Student t test. Viscosity measurement was performed by capillary viscometer. The resultant hematocrit and viscosity changes were measured. Then, at each step 0.5 mL of plasma was consecutively added in a total of 17 steps. Blood samples were taken from 32 healthy individuals and centrifuged for 5 min at 3000 rpm to obtain 2.5 mL of erythrocyte mass from each. In this research we evaluated the effect of hematocrit on increasing viscosity, and possible related changes in blood pressure, flow rate, and the equivalent physiologic compensation ratios. Increase in blood viscosity, defined as resistance to flow, is one factor in hypertension and atherosclerosis that contributes to the morbidity and mortality associated with tissue ischemia.
