Blood Donation Process: Blood Transfusion: Merck Manual Home Edition

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Blood Donation Process

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Donating blood is very safe. The entire process of donating whole blood (that is, blood with all component cells) takes about 1 hour. Blood donors must be at least 17 years old and weigh at least 110 pounds (50 kilograms). 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. Certain conditions and factors can permanently or temporarily disqualify people from donating blood. Disqualifying factors typically are those that might make donation dangerous for the donor or risk transmitting a disorder to the recipient. The decision to accept or disqualify a donor can be complicated. The American Red Cross provides detailed information on their website Red Cross eligibility requirements for blood donation.

Did You Know...

Very few disorders permanently disqualify people from giving blood.

Most people can eventually give blood even if they are disqualified at first because most conditions that disqualify donors are temporary.

Donated blood is tested for many infections, so the chance of getting a disease from donated blood is very small.

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Some Conditions That Disqualify People From Donating Blood
Condition	Permanent or Temporary Disqualification	Comments
AIDS Participation in activities that increase the risk of HIV infection Homosexuality in males	Permanent	High-risk activities include use of intravenous drugs and sexual intercourse with a person who has HIV infection.
Anemia (a low level of hemoglobin in the blood)	Temporary	People can donate blood after the anemia resolves.
Asthma, severe	Permanent	—
Bleeding disorders, congenital	Permanent	—
Cancers involving blood cells (for example, leukemia, lymphoma, or myeloma)	Permanent	People cannot donate even if they are cancer-free.
Cancers, other	Temporary	People may donate if they are cancer-free and treatment was completed more than 12 months previously. People with mild, treatable forms (such as small skin cancers) may be able to donate before 12 months.
Drugs (some), such as acitretinSome Trade Names SORIATANE , dutasterideSome Trade Names AVODART , etretinate, finasterideSome Trade Names PROSCAR , and isotretinoinSome Trade Names ACCUTANE	Temporary	How long people have to wait depends on the drug. Most drugs do not disqualify people from donating blood.
Heart disease, severe	Permanent	—
Hepatitis, illness	Permanent	People who have ever had hepatitis due to a virus cannot donate blood.
Hepatitis, exposure to	Temporary	People must wait 12 months after possible exposure (for example, living with or having sex with a person with hepatitis, being incarcerated in a correctional facility for more than 72 hours, or having a human bite that broke the skin).
High blood pressure	Temporary	People can donate after their blood pressure is controlled.
Possible exposure to prion diseases, such as variant Creutzfeldt-Jakob disease (also called mad cow disease—see Prion Diseases: Overview of Prion Diseases)	Permanent	Exposure may occur when People have used insulin derived from cows. People have spent time in Europe since 1980 (ranging from more than 3 months to 5 years, depending on the country) U.S. military personnel live on bases in Europe.
Malaria or exposure to malaria	Temporary	People must wait 1–3 years.
Pregnancy	Temporary	Women must wait 6 weeks after giving birth.
Major surgery if recent	Temporary	—
Tattoos	Temporary	People must wait 12 months.
Transfusions	Temporary or permanent	People who received a transfusion in the United States must wait 12 months. People who received a transfusion in the United Kingdom since 1980 or in certain African countries since 1977 may not donate.
Vaccines (some)	Temporary	How long people have to wait depends on the vaccine.
HIV = human immunodeficiency virus.

Some Conditions That Disqualify People From Donating Blood

Condition

Permanent or Temporary Disqualification

Comments

AIDS Participation in activities that increase the risk of HIV infection Homosexuality in males	Permanent	High-risk activities include use of intravenous drugs and sexual intercourse with a person who has HIV infection.
Anemia (a low level of hemoglobin in the blood)	Temporary	People can donate blood after the anemia resolves.
Asthma, severe	Permanent	—
Bleeding disorders, congenital	Permanent	—
Cancers involving blood cells (for example, leukemia, lymphoma, or myeloma)	Permanent	People cannot donate even if they are cancer-free.
Cancers, other	Temporary	People may donate if they are cancer-free and treatment was completed more than 12 months previously. People with mild, treatable forms (such as small skin cancers) may be able to donate before 12 months.
Drugs (some), such as acitretinSome Trade Names SORIATANE , dutasterideSome Trade Names AVODART , etretinate, finasterideSome Trade Names PROSCAR , and isotretinoinSome Trade Names ACCUTANE	Temporary	How long people have to wait depends on the drug. Most drugs do not disqualify people from donating blood.
Heart disease, severe	Permanent	—
Hepatitis, illness	Permanent	People who have ever had hepatitis due to a virus cannot donate blood.
Hepatitis, exposure to	Temporary	People must wait 12 months after possible exposure (for example, living with or having sex with a person with hepatitis, being incarcerated in a correctional facility for more than 72 hours, or having a human bite that broke the skin).
High blood pressure	Temporary	People can donate after their blood pressure is controlled.
Possible exposure to prion diseases, such as variant Creutzfeldt-Jakob disease (also called mad cow disease—see Prion Diseases: Overview of Prion Diseases)	Permanent	Exposure may occur when People have used insulin derived from cows. People have spent time in Europe since 1980 (ranging from more than 3 months to 5 years, depending on the country) U.S. military personnel live on bases in Europe.
Malaria or exposure to malaria	Temporary	People must wait 1–3 years.
Pregnancy	Temporary	Women must wait 6 weeks after giving birth.
Major surgery if recent	Temporary	—
Tattoos	Temporary	People must wait 12 months.
Transfusions	Temporary or permanent	People who received a transfusion in the United States must wait 12 months. People who received a transfusion in the United Kingdom since 1980 or in certain African countries since 1977 may not donate.
Vaccines (some)	Temporary	How long people have to wait depends on the vaccine.
HIV = human immunodeficiency virus.

Generally, donors are not allowed to give blood more than once every 56 days. The practice of paying donors for blood has almost disappeared because it encouraged needy people to present themselves as donors and then sometimes to deny having any conditions that would disqualify them.

A person who is deemed eligible to donate blood 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 thoroughly, 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 (about 450 milliliters). 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, selected other viral disorders, and syphilis.

Testing Donated Blood for Infections

Blood transfusions can transmit infectious organisms carried in the donor's blood. That is why health officials have restricted blood donor eligibility and made blood testing thorough. All blood donations are tested for infection with the organisms that cause viral hepatitis, AIDS, selected other viral disorders (such as West Nile virus), Chagas disease, and syphilis.

Viral Hepatitis

Donated blood is tested for infection with the viruses that cause the types of viral hepatitis (types B and C) that are transmitted by blood transfusions.

These tests cannot identify all cases of infected blood, but with the rigorous testing and donor screening procedures, a transfusion poses almost no risk of transmitting hepatitis C. The current risk is 1 infection for every 2,600,000 units of blood transfused.

Hepatitis B remains the most common potentially serious disorder transmitted by blood transfusions, with a current risk of about 1 infection for every 200,000 units of blood transfused.
AIDS

In the United States, donated blood is tested for the human immunodeficiency virus (HIV), the cause of AIDS. The test is not 100% accurate because it will not be positive during the first few weeks after a person has acquired HIV infection. However, potential donors are interviewed as part of the screening process. Interviewers ask about risk factors for AIDS—for instance, whether the potential donors or their sex partners have injected drugs or had sex with a man who has male sex partners. Because of the blood test and the screening interview, the risk of contracting HIV infection through a blood transfusion is extremely low—1 in 2,600,000 according to recent estimates.
Syphilis

Blood transfusions rarely transmit syphilis. Not only are blood donors screened and donations tested for the organism that causes syphilis, but the donated blood is also refrigerated at low temperatures, which kills the infectious organisms.