Blood donations and blood banking

Facts about blood banking

• About 38,000 units of red blood cells are needed every day (2006).
• The number of blood units donated is about 16 million a year (2006).
• There are approximately 9.5million volunteer blood donors (2006).
• Five million patients receive transfusions of blood units each year (2006).
• Each unit of blood is broken down into components, such as red blood cells, plasma and platelets.
• One unit of whole blood, once separated, may be transfused to several patients, each with different needs.
• Annually, more than 23 million units of blood components are transfused.

Blood types

According to the American Association of Blood Banks, distribution of blood types in the United States is as follows:    

• O Rh-positive – 39 percent
• A Rh-positive – 31 percent
• B RH-positive – 9 percent
• O Rh-negative – 9 percent
• A Rh-negative – 6 percent
• AB Rh-positive – 3 percent
• B Rh-negative – 2 percent
• AB Rh-negative – 1 percent

Who are the blood donors?

Most blood donors are volunteers. However, sometimes a patient may want to donate blood a couple of weeks before undergoing surgery, so that his/her blood is available in case a blood transfusion is necessary. Donating blood for yourself is called an autologous donation.

Regulations for blood donation

To ensure the safety of the blood donation process and available blood supply, volunteer blood donors must pass certain criteria, including the following:

• must be at least 16 to 17 years old
• must be in good health
• must weigh at least 110 pounds
• must pass the physical and health history examination given prior to donation

Some states permit persons younger than 16 or 17 years to donate blood with parental consent.

What are the components of blood?

Blood has many components and each serves many functions:

• Red blood cells carry oxygen to the tissues in the body and are commonly used in the treatment of anemia.
• Platelets help the blood to clot and are used in the treatment of leukemia and other forms of cancer.
• White blood cells help to fight infection, and aid in the immune process.
• Plasma is the watery, liquid part of the blood in which the red blood cells, the white blood cells, and platelets are suspended. Plasma is needed to carry the many parts of the blood through the bloodstream. Plasma serves many functions, including the following:
  • helps to maintain blood pressure provides proteins for blood clotting
  • balances the levels of sodium and potassium
• Cryoprecipitate AHF is a portion of the plasma that contains clotting factors that help to control bleeding.

Albumin, immune globulins, and clotting factor concentrates may also be separated and processed for transfusions.