Who can donate 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.
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
• 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. Who knows? Maybe someone close to you will be the recipient of your blood donation.
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 are the components of blood? Blood is made up of several components. These components can be separated in the laboratory so that they can be transfused into multiple patients, each with different needs, since rarely will a person need all of the components within whole blood. These components include:

• Red blood cells – main cellular element in the blood; carry oxygen to the body tissues; used in the treatment of anemia resulting from, for example, kidney failure, gastrointestinal bleeding, or blood loss during trauma or surgery
• Platelets – cellular elements needed for blood to clot; used in the treatment of leukemia and other types of cancer and conditions in which patients have a shortage of platelets (e.g., thrombocytopenia) or abnormal platelet function to control bleeding
• Plasma – straw-colored fluid part of blood in which the red and white blood cells and platelets are suspended; helps to maintain blood pressure and the fluid-electrolyte and acid-base balances of the body and transport wastes; used to help control bleeding when no coagulation factor-specific concentrate is available
• Cryoprecipitate antihemophilic factors (AHF) – part of the plasma that contains clotting factors to help control bleeding in people with hemophilia and von Willebrand's disease; only used in most places in the U.S. when viral-inactivated concentrates containing Factor VIII and von Willebrand factor are unavailable or, at times, during surgery as a hemostatic preparation (fibrin sealant)
• White blood cells – cellular elements that fight infection and function in the immune process, including allergic reactions; one type, called granulocytes, can be transfused to fight infections that are unresponsive to antibiotic therapy, although the effectiveness of this form of treatment is still being investigated

Separation of these components is performed by first treating the blood to prevent clotting and then letting the blood stand. Red blood cells settle to the bottom, while plasma migrates to the top. Using a centrifuge to spin out these components can speed up the process. The plasma is then removed and placed in a sterile bag. It can be used to prepare platelets, plasma, and cryoprecipitate antihemophilic factors, again with the help of a centrifuge to separate out the platelets. Plasma may be pooled with that from other donors and processed further (fractionated) to provide purified plasma proteins, such as albumin, immunoglobulin, and clotting factor concentrates. For more information, see the detailed list of Blood and Components.