All Medical Procedures

If you are planning to donate blood and bone marrow, you've agreed to allow doctors to draw blood stem cells from your blood or bone marrow for transplantation. Blood stem cells are the cells that make all of the body's blood cells. They form and mature in the bone marrow, and are then released into the bloodstream. Although they're called "stem cells," these cells aren't the same as the embryonic stem cells studied in therapeutic cloning and other types of research.

In the past, surgery to draw marrow from the bone was the only way to collect blood stem cells. Today, however, it's more common to collect blood stem cells directly from the blood. This is called peripheral blood stem cell (PBSC) donation.

Blood stem cells can also be collected from umbilical cord blood at birth. However, only a small amount of blood can be retrieved from the umbilical cord, so this type of transplant is generally reserved for children and small adults.

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.

In a blood transfusion, donated blood is added to your own blood. A blood transfusion may also be done to supplement various components of your blood with donated blood products. In rare cases, a blood transfusion is done with blood that you've donated ahead of time before you undergo surgery.

During a typical blood transfusion, certain parts of blood are delivered through an intravenous (IV) line that's placed in one of the veins in your arm. A blood transfusion usually takes one to two hours, though in an emergency it can be done much faster.

A blood transfusion boosts blood levels that are low, either because your body isn't making enough or because blood has been lost during surgery, injury or disease.