Plasma is collected through a process called "plasmapheresis." When you come in to donate, a needle is placed in your vein and your blood is pumped into a specialized spinning device that separates the plasma from the other whole blood components, such as red and white blood cells and platelets. While the plasma is collected, the other blood components are filtered into a reservoir. Once the reservoir is full, your red and white blood cells and platelets are returned to your body.