Donating plasma involves the process of giving the liquid portion of the blood, which is called plasma. During a plasma donation, blood is drawn from the donor's arm and passed through a machine that separates the plasma from the blood cells. The red blood cells and platelets are then returned to the donor along with some saline. Plasma donations are used to help trauma, burn, and shock patients, as well as people with severe liver disease or multiple clotting factor deficiencies. Donors must generally be 18 years of age and weigh at least 110 pounds. The process is similar to giving blood and is safe, taking about 1 to 2 hours. Donors can typically donate plasma as often as every 28 days