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Transfusion Medicine

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Donating Blood

Blood donors are volunteers who provide a greatly needed service. About 4 million patients receive blood transfusions each year, and approximately 40,000 units of red blood cells are needed every day. Although 14 million blood units are donated a year, more volunteers are needed to keep the blood supply at an adequate volume. According to AABB, although an estimated 38% of the U.S. population is eligible to donate blood at any given time, less than 10% actually do so annually.

Who can donate blood?
Donors must meet certain criteria to ensure their safety and the safety of the recipients. Rules of eligibility have been established by the U.S. Food and Drug Administration (FDA), although some donor centers may have additional requirements.

Donors must:

  • Be at least 17 years of age (although some states permit younger people to donate if they have parental consent)
  • Be in good health
  • Weigh at least 110 pounds (Some facilities will allow people who weigh less to donate, but they must then adjust the amount of blood collected and the amount of anticoagulant in the collection bags.)
  • Pass a physical and health history examination prior to donation

The physical includes measurement of blood pressure, pulse, and temperature as well as a test for anemia, which requires just a few drops of blood from your finger.

To protect the health of both the donor and the recipient, the health history questionnaire asks about potential exposure to transfusion-transmissible diseases, such as viruses like HIV, hepatitis B and C, and HTLV I and II as well as parasites that cause malaria, babesiosis, and Chagas disease.

Certain people are not permitted to donate blood for health concerns. This includes:

  • Anyone who has ever used illegal intravenous (IV) drugs
  • Men who have had sexual contact with other men since 1977; in May 2015, the FDA developed a draft guidance that may be finalized by the end of the year. If finalized, it would change this restriction to men who have had sexual contact with men in the last 12 months.
  • Hemophiliacs
  • Anyone with a positive test for HIV
  • Men and women who have ever taken money, drugs, or other payment for sex since 1977
  • Anyone who has had hepatitis since his or her eleventh birthday
  • Anyone who has had babesiosis or Chagas disease
  • Anyone with Crueutzfeldt-Jakob disease (CJD) or who has an immediate family member with CJD
  • Because of CJD, anyone who has spent time in the United Kingdom between 1980-1996 that adds up to 3 months or more; anyone who, from 1980 to the present, spent time in Europe that adds up to 5 years or more; and anyone who received a blood transfusion in the UK between 1980 and the present.
  • Some travel or health problems may require a temporary deferral.

There also may be some restrictions if you are taking certain medications at the time of donation. You may be ineligible to donate or deferred for a period of time. For example, the FDA has specified that individuals on Tegison (etretinate), human growth hormone, or bovine insulin from the United Kingdom must be deferred indefinitely. Those taking Proscar (finasteride), Propecia (finasteride), or Accutane (isotretinoin) will be deferred from donating for 4 weeks following last dose. Use of hepatitis B immune globulin results in a 12-month deferral and Soriatane (acitretin) is a 3-year deferral. In addition, if you are taking an antibiotic or any other medication for an infection, you will be evaluated and deferred temporarily. There also are varying deferral periods if you have been vaccinated recently. For a more complete list, review "Medications" in the American Red Cross's blood donation eligibility criteria.

Donors have a personal responsibility to help ensure the safety of the blood supply. You should express any concerns or questions you may have about past illnesses you had or may have been exposed to before donating.

Where can blood be donated?
Blood can be donated at community blood centers, hospital-based donor centers, or mobile sites temporarily set up in public areas like colleges, workplaces, and churches. There are hundreds of institutions involved in blood banking throughout the U.S.

For more information on where you can go to donate, visit AABB's online Locator.

What is donated and how often?
Usually one unit (about a pint) of blood is collected into a blood bag from a vein in the inner part of the elbow joint using a new, sterile needle. Your body replenishes the fluid lost during donation in 24 hours, but it may take up to 2 months to replace the lost red blood cells. Therefore, whole blood can be donated only once every 8 weeks. Two units of red blood cells can be donated at a time, using a process called red cell apheresis, every 16 weeks. Platelets can also be donated by apheresis, usually every 4 weeks.

What is autologous blood donation?
Another type of blood donation is autologous donation. This refers to transfusions in which the blood donor and the transfusion recipient are the same. People may elect to do this before a surgical procedure in which the likelihood of needing a transfusion is high. Although there are still risks with this process, autologous donation minimizes many of them because it is the person's own blood that is being returned to his or her body.

A person can donate their blood up until 72 hours prior to their surgery. Iron supplements or erythropoietin also may be prescribed to help increase the person's red blood cell count. Any blood that remains unused during the surgery is usually discarded. However, the blood can be transfused into another patient if it has been fully tested and is compatible with the recipient.

According to the National Blood Collection and Utilization Survey and AABB, autologous blood accounted for 0.7% of all donated blood in 2011. The use of this type of donation varies by location, and not all physicians recommend it. There has been some concern about low hematocrit levels following surgery in patients who donate autologous units. The decision should be made together by the patient and his or her doctor. Other options may be preferred, such as intra-operative blood salvage, in which any blood lost during the surgery can be collected and returned to the patient.

What happens to blood after it is donated?
When a unit of whole blood is donated, the components can be separated in the laboratory so that they can be transfused into multiple patients, each with different needs. Rarely will a person need all of the components that comprise whole blood.

Read more about Blood and Its Components.

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