AIDS--acquired immune deficiency syndrome--is the final and most serious stage of HIV disease, an infection caused by the human immunodeficiency virus. HIV can be transmitted from an infected person to another through sexual contact, use of contaminated needles, pregnancy, breastfeeding or--rarely--through blood transfusion.
The risk of contracting HIV through blood transfusion is very low in the United States, notes the American Cancer Society, because blood banks test all donated blood for HIV. The test is not 100 percent reliable, however, so a small risk of contracting HIV through a blood transfusion remains.
Scope
AIDS is the fifth leading cause of death in the United States among people ages 25 to 44, according to the University of Maryland Medical Center. Worldwide, approximately 25 million people have died from AIDS and, as of 2006, another 40 million people were living with HIV/AIDS.
More than 20 million whole blood, red cell concentrates, plasma or platelets transfusions are performed in the United States each year, indicates the U.S. Food and Drug Administration, or the FDA. The risk of being infected with HIV from a blood transfusion is lower than the risk of being killed by lightning, states the National Heart Lung and Blood Institute. Only about one in 2,000,000 units of donated blood might carry HIV and transmit it to the recipient.
Types
Transfusion is the process of giving whole blood or one of its components to an ill or injured patient through an intravenous line. There are two sources of the blood: a volunteer donor or the patient himself.
Autologous blood--donated by the patient and re-infused at a later time--is the safest source, but is generally only available to individuals scheduled for surgery within weeks after the donation. Most transfusions use blood donated by volunteers--allogeneic blood.
HIV/AIDS
A patient who mistakenly receives HIV-infected blood will contract the disease but may not have symptoms for 10 or more years. If the virus is not detected or treated, she will eventually develop AIDS, explains the University of Maryland Medical Center. HIV attacks the immune system, leaving the patient vulnerable to life-threatening cancers and infections. There is no cure for AIDS, but medication can alleviate symptoms and improve the patient's quality of life.
Donor Screening
Blood banks screen allogeneic donors to determine if their blood is safe to be given to another individual. Based upon the donor's responses to questions about previous illnesses, travel, IV drug use and sexual contacts, the blood bank may determine that the donor is in a high-risk group and ineligible to donate.
HIV Testing
All donated blood is tested for HIV before being released for transfusion. Nearly all cases of HIV contracted through a transfusion occurred before HIV testing began in 1985, according to the University of Maryland Medical Center. Still, the test cannot identify the virus when the blood concentration is very low, as it is when the individual has only recently been infected. The FDA points out that the failure rate of HIV testing is about one in 1,000,000.
Self-Deferral
Although U.S. blood banks test all donated blood, potential donors are still encouraged to self-defer by stopping the screening process if they suspect that their blood may be unsafe. In many donation centers, as a further safety measure, the donor is asked to affix one of two bar-coded stickers on the donation form: one indicates that the blood is safe for use by others and the other indicates that the blood is unsafe and should be discarded. Other centers may provide a different method for the donor to confidentially communicate that his blood should not be used, like a check mark or sticker on a separate form. This allows the donor to avoid embarrassment and continue with the donation, but prevents the blood from being used for transfusion.
References
- U.S. Food and Drug Administration: Keeping Blood Transfusions Safe: FDA's Multi-layered Protections for Donated Blood
- National Heart Lung and Blood Institute: What Are the Risks of a Blood Transfusion?
- American Cancer Society: Possible Risks of Blood Product Transfusions
- University of Maryland Medical Center: AIDS
- U.S. Food and Drug Administration: Blood Donations from Men Who Have Sex With Other Men
