Blood Transfusion

Risks of Blood Transfusion

The risks of blood transfusions include transfusion reactions (immune-related reactions), nonimmune reactions, and infections.

Immune-related reactions

Immune-related reactions occur when your immune system attacks components of the blood being transfused or when the blood causes an allergic reaction.

Most transfusion reactions occur because of errors made in matching the recipient's blood to the blood transfused. These administrative errors may occur because of mislabeled blood samples or misread labels. Much effort is made to prevent these errors; they occur about once in every 14,000 transfusions.¹ Even receiving the correct blood type sometimes results in a mild transfusion reaction.

These reactions may be mild or severe. Most mild reactions are not life-threatening when treated quickly. Even mild reactions, though, can be frightening. Severe transfusion reactions can be life-threatening.

There are several immune-related transfusion reactions.

• Nonhemolytic fever reactions cause fever and chills without destruction (hemolysis) of the red blood cells. This is the most common transfusion reaction. It can occur even when the blood has been correctly matched and administered. The more transfusions you receive, the greater your risk for this type of reaction. People who have had several transfusions are more likely to have nonhemolytic fever reactions or other types of immune system reactions. These problems occur because the body mistakes the new blood as harmful and makes specific antibodies to destroy it. Careful screening helps reduce the risk for these problems.²
• Hemolytic transfusion reactions destroy the transfused red blood cells when they are attacked by the person's immune system. This most commonly occurs if there is a mismatch with the ABO or Rh blood types, but some of the minor blood subtypes can also cause this severe reaction, which can be life-threatening.
• An immune reaction to platelets in transfused blood results in the destruction of the transfused platelets. People who develop this type of reaction may have difficulty finding blood that can be transfused without causing a reaction.
• On rare occasions, an immune reaction may take place that attacks the person's lungs (transfusion-related acute lung injury). This results in difficulty breathing and other symptoms. Most people recover fully from this type of reaction.

Mild allergic reactions may involve itching, hives, wheezing, and fever. Severe reactions that involve anaphylactic shock can be life-threatening.

Doctors will stop a blood transfusion if they think you are having a reaction. A reaction may turn out to be mild, but at the beginning, it is hard for doctors to know whether it will be severe.

Nonimmune reactions

Fluid overload is a common type of nonimmune reaction.

• Fluid overload can occur when you receive too much fluid through transfusions, especially if you have not experienced blood loss before the transfusion.
• Fluid overload may require treatment with medicines to increase urine output (diuretics) to rid your body of the excess fluid.

Very rarely, a person can develop iron overload after having many repeated blood transfusions. This condition, sometimes called acquired hemochromatosis, is often treated with medicine. Too much iron can have an effect on many organs in the body.

Infections

The transmission of viral infections, such as hepatitis B or C or HIV, through blood transfusions has become very rare because of the safeguards enforced by the U.S. Food and Drug Administration (FDA) on the collection, testing, storage, and use of blood. The risk of infection from a blood transfusion is higher in less developed countries, where such testing may not happen and paid donors are used.

It is possible for blood, especially platelets, to become contaminated with bacteria during or after donation. Transfusion with blood that has bacteria can result in a systemic bacterial infection. Because of the precautions taken in drawing and handling donated blood, this risk is small. There is a greater risk for bacterial infection from transfusions with platelets. Unlike most other blood components, platelets are stored at room temperature. If any bacteria are present, they will grow and cause an infection when the platelets are used for transfusion.

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Author:	Caroline Rea, RN, BS, MS	Last Updated: December 27, 2007
Medical Review:	Anne C. Poinier, MD - Internal Medicine Joseph O'Donnell, MD - Hematology/Oncology
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