By Mayo Clinic Staff

Blood donation is a voluntary procedure. You agree to have blood drawn so that it can be given to someone who needs a blood transfusion. Millions of people need blood transfusions each year. Some may need blood during surgery. Others depend on it after an accident or because they have a disease that requires blood components. Blood donation makes all of this possible.

There are several types of blood donation:

  • Whole blood. This is the most common type of blood donation, during which approximately a pint of whole blood is donated. The blood is then separated into its components — red cells, plasma, platelets.
  • Platelets. This type of donation uses a process called apheresis. During apheresis, the donor is hooked up to a machine that collects the platelets and some of the plasma, and then returns the rest of the blood to the donor.
  • Plasma. Plasma may be collected simultaneously with a platelet donation, or it may be collected without collecting platelets during an apheresis donation.
  • Double red cells. Double red cell donation is also done using apheresis. In this case, only the red cells are collected.
May 30, 2014