A device that spins test tubes at high speeds. The heavy, more dense, particles in the liquid settle to the bottom of the tube, and the lighter liquid goes to the top. When unclotted blood is centrifuged, the plasma goes to the top and the heavy red cells go to the bottom of the tube. The white blood cells are heavier than the plasma but lighter than the red blood cells, so they form a thin layer between the red blood cells and the plasma.
SEE: buffy coat
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