Many patients with rare and genetic disorders are relying on YOU. That's because blood contains plasma, a key ingredient in the treatments they need to survive...and the only way to get source plasma is from healthy donors. Plasma is the protein-rich, gold-colored liquid portion of blood that remains after red blood cells, white blood cells, platelets and other cellular components are removed. It all starts when a donor visits one of the more than 1,000 source plasma donation centers in North America and Europe.