The thin layer of white blood cells and platelets found above the packed red cells in centrifuged blood is called the

Buffy coat.

Explanation:

Between the plasma, and red blood cells the platelets, and white blood cells form a thin white layer which is known as Buffy coat following density gradient centrifugation of the blood.

Centrifugation is the process where the distinguish between cell fragments, and cell from the liquid intracellular matrix occurs. Centrifugation is a technique which separates the particles according to their size, density, viscosity and shape with the help of centrifugal force.

answer; i believe the answer is hydraulic action;