B Positive National Blood Services

Human blood is made up of three main components: red blood cells, white blood cells and plasma. Plasma is the yellow, liquid portion of blood that serves as the carrier for cells and other minor blood components. Though it is made up of mostly water, plasma is needed for its dissolved proteins, clotting factors and various antibodies.

Donating plasma is similar to donating blood. The process of donating plasma, otherwise known as plasmapheresis, takes approximately 30-50 minutes. During the donation process, plasma is separated from other blood components and kept while the red blood cells and other blood components are returned to your body. You can donate as often as twice a week (but not two days in a row).