Blood is almost never used in its whole form. Most patients requiring transfusions only need one or two of the many components that make up blood. It would be wasteful and sometimes harmful to give patients components they do not need.

Most blood is separated into blood components that can be used to treat three or more patients. Below are some of the products derived from whole blood:

• Red blood cells carry oxygen and are needed by surgical patients or to treat those with anemia. Red blood cells can also be washed and filtered to prevent adverse reactions in some sensitive patients. Sometimes rare red cell types are frozen to extend their storage period and help ensure that an adequate supply is always available.
• Platelet concentrates are blood elements that are an important part of the body's clotting system. They are used to control bleeding in the course of treatment of leukemia and other forms of cancer.
• Plasma is the yellow liquid portion of blood, which restores fluid volume in patients who have suffered from shock and provides a source of clotting proteins that stop bleeding.
• Cryoprecipitate is a part of plasma that contains specific clotting factors. It is used to treat clotting deficiencies like those found in people with hemophilia.
• Fractionation is the process of breaking down plasma. Some of the more common products are:
  • Albumin: used in the treatment of certain kidney and liver diseases. Because this product is easy to store and administer, it is used in the treatment of emergency cases like accident or shock victims.
  • Gamma globulin: used to modify or prevent measles and other infectious diseases such as some varieties of hepatitis.

How much blood is usually needed for various medical procedures?

Coronary Artery Bypass........................................................ 1 to 5 units
Fractured Hip/Joint Replacement............................................ 2 to 5 units
Cardiovascular Surgery.......................................................... 2 to 25 units
Bleeding Ulcer....................................................................... 3 to 30 units
Brain Surgery......................................................................... 4 to 10 units
Auto Accidents/Gunshot Wounds................................ up to 50 units
Organ Transplant......................................................... up to 100 units
Bone Marrow Transplant............................................. up to 2 units per day
Sickle Cell/Aplastic Anemia......................................... up to 4 per week
Cancer........................................................................ up to 8 per week