Blood Transfusion: Safer Than Ever
Each year, more than 4 million people need to undergo blood transfusion, reports the American Association of Blood Banks, or AABB. At no time since the first successful blood transfusion was performed in 1795 in the United States has this potentially life-saving procedure been as safe as it is today.
In the two decades since the AIDS virus appeared on the scene, the emergency blood supply in this country has become even safer. This improvement is a result of:
But no medical or surgical procedure is fail-safe.
The Risks: Few And Far Between
Despite the many safety measures in place, there are a few risks associated with blood transfusion. Keep in mind, however, that the benefits of this potentially life-saving procedure far outweigh the risks.
The few risks associated with blood transfusions can generally be divided into two broad categories:
In the United States, each unit of donated blood is tested for several different infectious diseases. They include hepatitis C and hepatitis B viruses, human immunodeficiency virus (HIV), human T-cell lymphotropic virus type 1 (HTLV-1) and syphilis.
According to the American Society of Anesthesiologists, your risk of contracting HIV, hepatitis C, hepatitis B or HTLV-1 from a blood transfusion is about one in 34,000 transfused units. Hepatitis B and hepatitis C account for 88 percent of this risk, the society reports.
HIV. HIV is a retrovirus that attacks the white blood cells, the body's main immune defense against foreign invaders. The AABB says the risk of exposure to HIV through a blood transfusion is one in 450,000 to one in 676,000 transfused units. This risk is expected to decrease now that the U.S. Food and Drug Administration (FDA) has approved nucleic acid amplification testing for routine use by blood banks and hospitals. This test identifies genetic HIV markers in blood earlier than other HIV screening tests do. These other tests require HIV antibodies to develop, which may take 20 to 80 days. Nucleic acid amplification testing narrows the period between the initial HIV infection and its earliest possible detection.
Hepatitis C and hepatitis B. Hepatitis is a disease characterized by liver inflammation. The risk of obtaining hepatitis C from a blood transfusion is about one in 103,000 transfused units, and the risk of hepatitis B is one in 63,000 transfused units. Routine screening for hepatitis C antibodies in donated blood began in 1990. Since then, screening has improved greatly. And, as with HIV, the risk of contracting hepatitis C will likely become even smaller now that the FDA has approved nucleic acid amplification testing for this virus.
HTLV-1. HTLV-1 is a retrovirus related to HIV. The risk of getting HTLV-1 from a blood transfusion is about one in 641,000 transfused units.
Syphilis. Syphilis is a bacterial disease that is sexually transmitted. Blood or a blood component — typically platelets — can become contaminated with the bacteria that cause syphilis when blood is first donated or when it is later processed for storage. However, syphilis is very rarely the result of a blood transfusion. Not only is all donated blood screened for this disease, it often is stored at low temperatures that do not support the survival of the bacteria.
Other bacterial infections. Septic reactions may develop following infusion of blood products that became contaminated with bacteria during collection, processing or storage. These dramatic, occasionally fatal, reactions may develop following transfusion of red blood cells, but more commonly occur following platelet transfusions. Approximately 1 per million red blood cell units may become contaminated with Yersinia enterocolitica or Pseudomonas, organisms that can multiply in low-temperature storage conditions. One in 10,000 platelet concentrates may become infected with a wide range of bacteria which can rapidly multiply in the room-temperature platelet storage conditions
Other potential risks. Other diseases that can be transmitted through a blood transfusion include cytomegalovirus, Lyme disease, Creutzfeldt-Jakob disease, mad cow disease, some herpesviruses, Epstein-Barr virus, brucellosis and leishmaniasis. However, actual cases acquired through blood transfusion are highly unusual. Similarly rare are diseases caused by parasites, including malaria, toxoplasmosis, babesiosis and Chagas' disease.
Despite the reduction in the risk of transfusion-related infectious disease over the past few years, noninfectious reactions continue to be a risk. However, improved administrative techniques have resulted in less frequent severe and fatal reactions from transfusions of incompatible blood.
Hemolytic transfusion reaction. A hemolytic transfusion reaction — a reaction that destroys red blood cells — is the most common and most deadly risk associated with transfusion. The risk of having a hemolytic transfusion reaction is about one in 33,000 transfused units. This occurs when the recipient's plasma and donor's red blood cells are incompatible, causing antibodies in the recipient's plasma to destroy the donor blood.
The FDA reports that hemolytic transfusion reactions occur twice as often as all infectious blood transfusions. These reactions are responsible for the majority of transfusion-related deaths, estimated to be one in 300,000 to one in 700,000 transfused units.
Hemolytic transfusion reactions are usually preventable because they often result from human error at some point in the transfusion process — be it a clerical or administrative error, a mistake in the collection of the blood sample or misidentification of the intended recipient.
Allergic reactions. An allergic reaction may stem from a recipient's sensitivity to allergens in transfused blood plasma. This type of reaction is likely to develop shortly after the transfusion starts. Rarely is an allergic reaction so severe as to pose a risk to the health of the recipient.
Anaphylaxis. Anaphylaxis is a type of severe allergic reaction that occurs very rarely as a result of blood transfusion. The exact cause is not always clear, although it involves a recipient's sensitivity to a donor's blood plasma. The reaction, which can lead to death, can occur during the blood transfusion or hours after it is over.
Febrile nonhemolytic transfusion reaction. A febrile nonhemolytic transfusion reaction is characterized by fever and chills. It is estimated that 1 percent of transfusions of red blood cells and 10 percent to 30 percent of transfusions with platelets are involved in this reaction. The cause is the incompatible mixing of antibodies and antigens between the blood of the donor and that of the recipient. Another cause is the presence of inflammatory cytokines in the stored unit of blood. This reaction develops after a transfusion is complete or near complete.
Transfusion-related acute lung injury. This condition results in shortness of breath within one to two hours of blood transfusion. Fluid rapidly builds up in the lungs. This is believed to occur as a result of an unpredictable interaction between antibodies in the donor's blood and the recipient's white blood cells. When this occurs, complexes form in the blood that injure the tiny blood vessels in the lungs, allowing fluid to leak into the air sacs. According to one estimate, as many as 40,000 people develop this transfusion-related complication each year.
Graft versus host disease. Graft versus host disease is a reaction that occurs when a recipient's immune system can't destroy incompatible white blood cells — specifically lymphocytes — from a transplanted organ, in this case the donor blood. It usually occurs in people whose immune systems are already compromised, either because of disease or immunosuppressant drugs. Symptoms can develop eight to 10 days after transfusion. Death may follow in a few weeks. Depletion of white blood cells and blood irradiation before the transfusion can reduce the risk of this reaction.
