The Donation Process
The entire process of donating whole blood takes about 1 hour. Blood donors must be at least 17 years old and weigh at least 110 pounds. In addition, they must be in good health: their pulse, blood pressure, and temperature are measured, and a blood sample is tested to check for anemia. They are asked a series of questions about their health, factors that might affect their health, and countries they have visited.
Conditions that permanently disqualify a person from donating blood include hepatitis B or C, heart disease, certain types of cancer (leukemia, lymphoma, and any type of cancer that has recurred after treatment or that has ever been treated with chemotherapy drugs), severe asthma, bleeding disorders, possible exposure to prion diseases (such as variant Creutzfeldt-Jakob disease (see Section 6, Chapter 90)), AIDS, and possible exposure to the human immunodeficiency virus (HIV, the virus that causes AIDS) due to high-risk behaviors (see Section 17, Chapter 199). Conditions that temporarily disqualify a person include malaria (if less than 3 years since last experiencing symptoms), cancer that has been treated with surgery or radiation (if less than 5 years since last receiving treatment), pregnancy, recent major surgery, poorly controlled high blood pressure, low blood pressure, anemia, the use of certain drugs, exposure to some forms of hepatitis, and a recent blood transfusion.
Generally, donors are not allowed to give blood more than once every 56 days. The practice of paying donors for blood has almost disappeared; it encouraged needy people to present themselves as donors and then sometimes to deny having any conditions that would disqualify them.
 See the figure Blood Typing.
After a person is deemed eligible to donate blood, he sits in a reclining chair or lies on a cot. A health care worker examines the inside surface of the person's elbow and determines which vein to use. After the area immediately surrounding the vein is cleaned, a needle is inserted into the vein and temporarily secured with a sterile covering. A stinging sensation is usually felt when the needle is first inserted, but otherwise the procedure is painless. Blood moves through the needle and into a collecting bag. The actual collection of blood takes only about 10 minutes.
The standard unit of donated blood is about 1 pint. Freshly collected blood is sealed in plastic bags containing preservatives and an anticlotting compound. A small sample from each donation is tested for the infectious organisms that cause AIDS, viral hepatitis, and syphilis.
 See the sidebar Testing Donated Blood for Infections.
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