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Blood FAQ

The following information is provided as a resource to the public and to professionals working in the area of transfusion medicine, as part of AABB's efforts to optimize the safety and care of patients and donors. This section includes basic facts about blood donation and transfusion, including frequently asked questions (see below), along with valuable material on patient blood management, emerging infectious diseases and the "Circular of Information for the Use of Human Blood and Blood Components."

How much blood is donated each year?
Who needs blood?
Who donates blood?
What are the criteria for blood donation?
Who should not donate blood?
Where is blood donated?
What is apheresis?
What is the most common blood type?
What tests are performed on donated blood?
How is blood stored and used?
What fees are associated with blood?
What is the availability of blood?
What can you do if you aren't eligible to donate?

How much blood is donated each year?

AABB estimates that 9.2 million volunteers donate blood each year, 30.9 percent of which are first time donors. According to the 2011 National Blood Collection and Utilization Report about 15.7 million units of whole blood and red blood cells were donated in the United States in 2011.

Typically, each donated unit of blood, referred to as whole blood, is separated into multiple components, such as red blood cells, plasma, platelets, and cryoprecipitated AHF (antihemophilic factor). Each component generally is transfused to a different individual, each with different needs.

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Who needs blood?

The need for blood is great. Every day in the U.S., approximately 41,000 units of blood are required in hospitals and emergency treatment facilities for patients with cancer and other diseases, for organ transplant recipients, and to help save the lives of accident/trauma victims. In 2011, nearly 21 million blood components were transfused. With an aging population and advances in medical treatments and procedures requiring blood transfusions, there is always a need for blood and blood components.

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Who donates blood?

Although an estimated 38 percent of the U.S. population is eligible to donate blood at any given time, less than 10 percent do so annually. According to studies, the average donor is a college-educated white male, between the ages of 30 and 50, who is married and has an above-average income. However, a broad cross-section of the population donates every day. Furthermore, these "average" statistics are changing, and women and minority groups are volunteering in increasing numbers to donate. Persons 65 years and older account for approximately 13 percent of the population, but they require 50 percent of all whole blood and red blood cells transfused. Using current screening and donation procedures, a growing number of blood banks have found blood donation by seniors to be safe and practical.

Patients scheduled for surgery may be eligible to donate blood for themselves, a process known as autologous blood donation. In the weeks before non-emergency surgery, an autologous donor may be able to donate blood that will be stored for their use.

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What are the criteria for blood donation?

Volunteer donors provide all blood used for transfusion in the United States. To be eligible to donate blood, a person must be in good health and generally must be at least 16 years of age (or in accordance with applicable state law). Minimum weight requirements may vary among facilities, but generally, donors must weigh at least 110 pounds. Most blood banks have no upper age limit. All donors must pass the physical and health history examinations prior to donation. Individuals may be temporarily ineligible to donate due to mild illnesses (colds or flu), unregulated hypertension, and diabetes and anemia. The donor's body replenishes the fluid lost from donation within 24 hours. It may take up to two weeks to replace the lost red blood cells. Whole blood can be donated once every eight weeks (56 days). Two units of red blood cells can be donated at one time, using a process known as red cell apheresis. This type of donation can be made every 16 weeks.

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Who should not donate blood?

  • Anyone who has ever used needles to take drugs, steroids, or any substance not prescribed by a doctor
  • Men who have had sexual contact with other men since 1977
  • Anyone with a positive test for HIV (AIDS virus)
  • Men and women who have engaged in sex for money or drugs since 1977
  • Anyone who has had hepatitis since his or her eleventh birthday
  • Anyone who has had babesiosis or Chagas disease
  • Anyone who has taken Tegison for psoriasis
  • Anyone who has risk factors for Crueutzfeldt-Jakob disease (CJD) or who has a blood relative with CJD
  • Anyone who has risk factors for vCJD, including:
    • Anyone who spent three months or more in the United Kingdom from 1980 through 1996
    • Anyone who received a blood transfusion in the United Kingdom or France from 1980 to the present
    • Anyone who has spent five years in Europe from 1980 to the present.

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Where is blood donated?

There are many places where blood donations can be made. Bloodmobiles (mobile blood drives on specially constructed buses) travel to many locations, making it easy for people to donate blood. Many people donate at blood drives at their places of work or at high schools, colleges, churches and other community organizations. People also can donate at community blood centers and hospital-based donor centers. You may use the online Locator or consult the yellow pages to locate a nearby blood center or hospital to donate.

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What is apheresis?

Apheresis, an increasingly common procedure, is the process of removing a specific component of the blood, such as platelets, red blood cells, plasma (liquid part of the blood) or granulocytes (white blood cells) and returning the remaining components to the donor. This process allows more of one particular part of the blood to be collected than could be separated from a unit of whole blood. 

The apheresis donation procedure takes longer than that of a whole blood donation. A whole blood donation takes about 10 to 20 minutes to collect the blood, while an apheresis donation may take about one to two hours depending on the blood component(s) that is being donated.

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What is the most common blood type?

The approximate distribution of blood types in the U.S. blood donor population is as follows. Distribution may be different for specific racial and ethnic groups and in different parts of the country:

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

In an emergency, anyone can receive type O red blood cells, and type AB individuals can receive red blood cells of any ABO type. Therefore, people with type O blood are known as "universal donors," and those with type AB blood are known as "universal recipients." In addition, individuals of all types can receive type AB plasma.

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What tests are performed on donated blood?

After blood has been drawn, it is tested for ABO group (blood type) and Rh type (positive or negative), as well as for any unexpected red blood cell antibodies that may cause problems in a recipient. Screening tests also are performed for evidence of donor infection with hepatitis B and C viruses, human immunodeficiency viruses HIV-1 and HIV-2, human T-lymphotropic viruses HTLV-I and HTLV-II, West Nile virus (WNV), and syphilis. Each donor is tested at least one time for antibodies to Trypanosoma cruzi, the parasite that causes Chagas disease.

The specific tests currently performed are listed below:

  • Hepatitis B surface antigen (HBsAg)
  • Hepatitis B core antibody (anti-HBc)
  • Hepatitis C virus antibody (anti-HCV)
  • HIV-1 and HIV-2 antibody (anti-HIV-1 and anti-HIV-2)
  • HTLV-I and HTLV-II antibody (anti-HTLV-I and anti-HTLV-II)
  • Serologic test for syphilis
  • Nucleic acid amplification testing (NAT) for HIV-1 ribonucleic acid (RNA), HCV RNA and WNV RNA
  • Nucleic acid amplification testing (NAT) for HBV deoxyribonucleic acid
  • Antibody test for Trypanosoma cruzi, the agent of Chagas disease 

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How is blood stored and used?

Each unit of whole blood normally is separated into several components. Red blood cells may be stored under refrigeration for a maximum of 42 days, or they may be frozen for up to 10 years. Red cells carry oxygen and are used to treat anemia or blood loss. Platelets are important in the control of bleeding and are generally used in patients with leukemia and other forms of cancer. Platelets are stored at room temperature and may be kept for a maximum of five days. Plasma can be stored frozen for a year before being thawed and transfused.  Plasma serves as a source of plasma proteins for patients who are deficient in or have defective plasma proteins and is generally indicated for management of preoperative or bleeding patients who require replacement of multiple plasma coagulation factors.

Cryoprecipitated AHF, which contains only a few specific clotting factors, is made from fresh frozen plasma and may be stored frozen for up to one year. Granulocytes are sometimes used to fight infections, although their efficacy is not well established. They must be transfused within 24 hours of donation.

Other products manufactured from blood include albumin, immune globulin, specific immune globulins, and clotting factor concentrates. Commercial manufacturers commonly produce these blood products.

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What fees are associated with blood?

While donated blood is free, there are significant costs associated with collecting, testing, preparing components, labeling, storing and shipping blood; recruiting and educating donors; and quality assurance. As a result, processing fees are charged to recover costs. Processing fees for individual blood components vary considerably. Processing fees for one specific component also may vary in different geographic regions. Hospitals charge for any additional testing that may be required, such as the crossmatch, as well as for the administration of the blood.

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What is the availability of blood?

The blood supply varies among the many regions throughout the U.S. The blood supply level also fluctuates throughout the year. Factors impacting blood inventories often include holidays/travel schedules, inclement weather and illness. Historically, blood collections can be low during the winter and summer months. In addition, recommended guidance by the Food and Drug Administration can eliminate, or defer, donors who may be at risk for transmitting a transfusion-transmissible disease such as variant Creutzfeldt-Jakob disease (vCJD) - the human variety of the disease that is commonly known as "mad-cow" disease and malarias. Such guidance can reduce the number of people who are eligible to donate. A reduction in donor turnout can put our nation's blood inventory at a critical low.

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What can you do if you aren't eligible to donate?

While a given individual may be unable to donate, he or she may be able to recruit a suitable donor. Blood banks are always in need of volunteers to assist at blood draws or to organize mobile blood drives. In addition, monetary donations are always welcome to help ensure that blood banks can continue to provide safe and adequate blood to those in need.

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