Centrifuged Blood and Vacutainer tubes

ABOUT CENTRIFUGED BLOOD

BLOOD is centrifuged to separate it into its various components inside a centrifuge that spins at high speed, exerting a force which isolates the blood into its several components.  Centrifuged blood consists typically of three coloured layers:

• A straw-coloured top layer comprises the liquid portion of blood—plasma—at c 55% of the total blood volume. 

• A thin plasma layer of white blood cells and platelets. 

• A lower layer compromising c 45% of the total is the red blood cells and may appear bright red or dark red depending upon the oxygen content of the cells.

BLOOD CELLS are leukocytes (white and erythrocytes (red)

BLOOD PLASMA is a yellowish substance into which blood cells are suspended. Plasma comprises water and various dissolved molecules including glucose, salts, proteins, clotting factors, immunoglobulins, hormones, and carbon dioxide from metabolic processes. 

CENTRIFUGES for blood separation make use of either a fixed-angle rotor or a swing-out rotor such as the system from Ariston Dental.  Ideally, a centrifuges should be chosen that has the potential to handle tubes of numerous capacities.  Swing-out rotor centrifuges enable particles to deposit uniformly at the tube’s base and often can utilise lower centrifugal forces for less energy consumption and similar outcomes.  By comparison, a fixed-angle rotor spins blood to the opposite side of the tube, from which it slides down to the base. Fixed angle devices use higher centrifugal forces which has the benefit of quicker separation.

CENTRIFUGE CYCLES.  Each technique relies on a different tube, time and centrifuge cycle.  Tpically a centrifuge speed of ±4000 -6500 RPM is considered adequate while a centrifuge speed of ±6500 RPM would be ideally suited for the majority of the research applications.  Swing-out rotor centrifuges may achieve the same outcome at the lower RPM range.