What is whole blood viscosity low cut, medium cut, and high cut

Whole blood viscosity at low, medium, and high shear rates refers to the measurement of blood viscosity indicators at different shear rates, mainly used to evaluate blood fluidity and microcirculation status. Whole blood viscosity testing usually includes three parameters: low shear rate reflecting red blood cell aggregation, medium shear rate reflecting blood transition flow state, and high shear rate reflecting red blood cell deformability. Abnormal values may be related to blood hypercoagulability, thrombus risk, or microcirculation disorders.

The increase of whole blood viscosity under low shear rate indicates the increase of erythrocyte aggregation, which is common in metabolic diseases such as hyperlipidemia and diabetes. At this time, blood flows slowly in the capillaries, making it easy to form small blood clots. The medium shear rate viscosity reflects the transitional characteristics of blood from an aggregated state to a dispersed state, and numerical abnormalities may indicate early cardiovascular disease. Abnormal high shear rate viscosity is usually associated with decreased deformability of red blood cells, and is more common in hereditary spherocytosis or long-term hypoxic diseases, which can lead to insufficient oxygen supply to tissues.

requires fasting venous blood collection and measurement using a rotary viscometer at a constant temperature of 37 ℃. There are differences in reference values among different age groups. The reference range for low shear viscosity in adult males is 8-12 mPa · s, for medium shear it is 5-8 mPa · s, and for high shear it is 3-5 mPa · s. Women typically have 0.5-1mPa · s lower hormone levels than men. Pregnant women may experience physiological decline, while dehydrated patients may experience pseudo elevation. Maintaining appropriate drinking water, regular aerobic exercise, and controlling oil intake can help maintain normal blood viscosity. People over 40 years old are recommended to undergo testing once a year, and those who already have cardiovascular and cerebrovascular diseases need to have a follow-up every 3-6 months. If the three indicators remain abnormal, further examination of coagulation function, hemorheology, and other items is necessary. If necessary, antiplatelet drugs should be used under the guidance of a doctor to improve microcirculation.