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Everybody has it. Everybody needs it.

Everyday, someone needs blood. Since blood cannot be manufactured outside the body, donors play a vital role in the health of our region. About 200 blood donors are needed every day to help meet the needs of Hawaii's patients.

There are many reasons patients need blood. The major reasons are cancer, heart and blood vessel disease, disease of the gastrointestinal tract, and emergencies including car accidents and burns. The amount of blood each patient needs depends on the situation.

Patient's Blood Needs per Situation

Automobile Accident:
  • 50 units of blood
  • 20 units of platelets
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


Blood Types

Although all blood is made of the same basic elements, not all blood is alike. In fact, there are four common human blood groups determined by the presence or absence of two chemical markers, or antigens “A” and “B” on the surface of red blood cells. This classification of human blood types is known as the ABO Blood Group System.


How Blood Cells Work

Blood cells fight infection, carry oxygen and help control bleeding. They are produced in bone marrow, especially the vertebrae, ribs, hips, skull and sternum. Among other components, blood cells consist of red cells, white cells, platelets and plasma.

Red cells

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.


White cells

White cells defend the body.
White cells are the body's primary defense against infection. They can move out of the blood stream and reach tissues being invaded.



Platelets help control bleeding.
Platelets are small fragments of cells in the blood that control bleeding. They form clusters to plug small holes in blood vessels and assist in the clotting process.



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, hormones and proteins including clotting factors.


Blood History

The Discovery of the ABO Blood Group System

In 1900, Austrian scientist Karl Landsteiner discovered that the sera from some people reacted with the red blood cells of other people. He originally identified three blood groups: A, B and C (later named O).  Consequently, type AB was found and all four blood type were identified, forming the ABO Blood Group system.

The blood group to which a person belongs is genetically inherited from one’s parents. Since mixing blood from two individuals may cause the destruction of red blood cells and can have fatal consequences, it is very important that blood types are matched prior to a blood transfusion.

Advances in Safety and Use

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, nearly every blood donation is fully utilized. Elements of blood can be separated by centrifuge. Plasma can be preserved by freezing. Each blood element can be used to treat different diseases.

Blood is tested for diseases it may carry, and any blood testing positive for a disease is destroyed.