Blood transfusions are generally considered to be safe. But they do carry some risk of complications. Complications may happen during the transfusion or not for weeks, months or even years afterward. They include the following:

Allergic reaction and hives

If you have an allergic reaction to the transfusion, you may experience hives and itching during the procedure or very soon after. This type of reaction is usually treated with antihistamines. Rarely, a more serious allergic reaction causes difficulty breathing, low blood pressure and nausea.


If you quickly develop a fever during the transfusion, you may be having a febrile transfusion reaction. Your doctor will stop the transfusion to do further tests before deciding whether to continue. A febrile reaction can also occur shortly after the transfusion. Fever may be accompanied by chills and shaking.

Acute immune hemolytic reaction

This is a very rare but serious transfusion reaction in which your body attacks the transfused red blood cells because the donor blood type is not a good match. In response, your immune system attacks the transfused red blood cells, which are viewed as foreign. These destroyed cells release a substance into your blood that harms your kidneys. This usually occurs during or right after a transfusion. Signs and symptoms include fever, nausea, chills, lower back or chest pain, and dark urine.

Lung injury

Transfusion-related acute lung injury (TRALI) is thought to occur due to antibodies or other biologic substances in the blood components. With TRALI, the lungs become damaged, making it difficult to breathe. Usually, TRALI occurs within one to six hours of the transfusion. People usually recover, especially when treated quickly. Most people who die after TRALI were very sick before the transfusion.

Bloodborne infections

Blood banks screen donors for risk factors and test donated blood to reduce the risk of transfusion-related infections. Infections related to blood transfusion still rarely may occur. It can take weeks or months after a blood transfusion to determine that you've been infected with a virus, bacterium or parasite.

The National Institutes of Health offers the following estimates for the risk of a blood donation carrying an infectious disease:

  • HIV — 1 in 2 million donations, which is lower than the risk of being killed by lightning
  • Hepatitis B — 1 in 205,000 donations
  • Hepatitis C — 1 in 2 million donations

Delayed hemolytic reaction

This type of reaction is similar to an acute immune hemolytic reaction, but it occurs much more slowly. Your body gradually attacks the donor red blood cells. It could take one to four weeks to notice a decrease in red blood cell levels.

Iron overload

If you receive multiple blood transfusions, you may end up with too much iron in your blood. Iron overload (hemochromatosis) can damage parts of your body, including the liver and the heart. You may receive iron chelation therapy, which uses medication to remove excess iron.

Graft-versus-host disease

Transfusion-associated graft-versus-host disease is a very rare condition in which transfused white blood cells attack the recipient’s bone marrow. This disease is usually fatal. It is more likely to affect people with severely weakened immune systems, such as those being treated for leukemia or lymphoma. Signs and symptoms include fever, rash, diarrhea and abnormal liver function test results. Irradiating the blood before transfusing it reduces the risk.

April 01, 2015