In addition to whole blood donation, there are ways to donate specific components, such as platelets or a double unit of red cells. In contrast to whole blood donation, this type of donation allows the donor to give only the desired component and have the remaining blood components return to their body during the donation process. This happens through a process called apheresis (see picture below), a Greek word meaning "a taking away."
Blood Cells Are Produced In Bone Marrow
Red cells, white cells and platelets are made in the marrow of bones, especially the vertebrae, ribs, hips, skull and sternum. These essential blood cells fight infection, carry oxygen and help control bleeding.
Plasma Carries Blood Cells
Plasma is a pale yellow mixture of water, proteins and salts. One of the functions of plasma is to act as a carrier for blood cells, nutrients, enzymes and hormones. Plasma can be stored in a frozen state for up to one year. It is used to treat bleeding disorders and burn patients.
Red Cells Deliver Oxygen
Red cells are disc-shaped cells containing hemoglobin, which enables the cells to pick up and deliver oxygen to all parts of the body. Red Blood Cells can be stored under refrigeration for up to 42 days. They are used to treat sickle cell and anemia as well as during surgery and trauma that results in blood loss.
Platelets Help Control Bleeding
Platelets are small cells in the blood that control bleeding. They form clusters to plug small holes in blood vessels and assist in the clotting process. Platelets are stored at room temperature and must be used within five days. They are used to treat cancer and during some surgeries, such as organ transplant.
Cryoprecipitate Help Blood to Clot
Cryoprecipitate is made from frozen plasma. It helps blood to clot, especially for patients who have certain types of bleeding disorders. Cryoprecipitate can be stored in a frozen state for up to one year. It is used to treat hemophilia, a bleeding disorder.
White Blood Cells Protect Against Infection
These are not typically transfused and are filtered out through a process called leukoreduction.
The Need for Blood
Most people will require a blood transfusion at some point in their lives. To meet patient needs for blood and blood components, the Blood Center requires more than 2,000 donations from volunteer blood donors every week. Each year those donations are used to help more than 200,000 patients in their recovery from illness or injury.
Each donation of whole blood can be used to produce as many as four different products that can be transfused to patients. How can this be true? After the donation, blood is separated into its components (red blood cells, platelets and plasma) and fourth product, cryoprecipitate, can be processed from the plasma. White blood cells are removed through a process called leukoreduction (pictured, at top right).
Major Reasons Patients Need Blood
- Heart and blood vessel disease
- Disease of the gastrointestinal tract
- Emergencies such as car accidents and burns
Examples (quantities are estimated)
- Automobile Accident - 50 units of blood
- Heart Surgery- 6 units of blood, 6 units of platelets
- Organ Transplant - 40 units of blood, 30 units of platelets, 20 bags of cryoprecipitate, 25 units of fresh frozen plasma
- Bone Marrow Transplant - 120 units of platelets, 20 units of blood
- Burn - 20 units of platelets
Key Developments in the History of Blood Transfusions
In 1898, it was discovered that inherited differences in people’s red cells were the cause of many of the incompatibilities seen with transfusions. Four blood types were identified. During World War I, when human blood was needed for transfusions for wounded soldiers, studies of how to preserve and transport blood began.
Not until World War II, however, did the development of effective preservative solutions make blood transfusions widely and safely available. There have been many advances since then, including the discovery of additional types of blood such as the Rh-positive and Rh-negative classifications.
Today, thanks to these advances, full utilization is made of nearly every blood donation. Elements of blood can be separated by centrifuge. Plasma can be preserved by freezing. Each blood element can be used to treat different diseases.
In addition, prospective donors are thoroughly screened before giving blood, and every donation is tested for diseases it may carry, and any blood testing positive for a disease is destroyed.
Millions of times each year in the United States, human blood is required to save the lives of people suffering from accidents and disease. There is no way to manufacture human blood outside the body. That is why the Blood Center plays such a vital role in the healthcare of our region.