Blood viscosity is the intrinsic resistance of blood to flow at vessel walls and represents the thickness and stickiness of blood. Increased whole blood viscosity (WBV) has been reported as a cardiovascular risk factor. The dynamic range of WBV is relatively wide, i.e., 4–45 centipoise (cP) (40–450 milliPoise (mP)), highlighting the potential utility of this parameter as a biomarker to provide an incremental prediction of clinical outcomes of cardiovascular disease and to modify the therapeutic modalities.