A hemolytic transfusion reaction is a serious complication that can occur after a transfusion of blood. The red blood cells that were given in the transfusion are destroyed by the patient's immune system.
There are other types of allergic transfusion reactions that do not cause hemolysis.
Blood transfusion reaction
Blood is classified into different blood types called A, B, AB, and O.
Your immune system can usually tell its own blood cells from blood cells from those of another person. If other blood cells enter your body, your immune system may already have antibodies against them. These antibodies will work to destroy the blood cells that your immune system does not recognize.
Another way blood cells may be classified is by Rh factors. People who have Rh factors in their blood are called "Rh positive." People without these factors are called "Rh negative." Rh negative people form antibodies against Rh factor if they receive Rh positive blood.
There are also other factors to identify blood cells, in addition to ABO and Rh.
Blood that you receive in a transfusion must be compatible with your own blood. This means that your body does not have antibodies against the blood you receive.
Most of the time, blood transfusion between compatible groups (such as O+ to O+) does not cause a problem. Blood transfusion between incompatible groups (such as A+ to O-) causes an immune response. This can lead to a serious transfusion reaction. The immune system attacks the donated blood cells, causing them to burst.
Today, all blood is carefully screened. Transfusion reactions very rare.
Therapy can prevent or treat the severe effects of a hemolytic transfusion reaction. If symptoms occur during the transfusion, the transfusion must be stopped immediately. Blood samples from the person getting the transfusion and from the donor may be tested to tell whether symptoms are being caused by a transfusion reaction.
Mild symptoms may be treated with:
Acetaminophen, a pain reliever to reduce fever and discomfort
Fluids given through a vein (intravenous) and other medicines to treat or prevent kidney failure and shock.
The outcome depends on how bad the reaction is. The disorder may disappear without problems. Or, it may be severe and life-threatening.
Tell your health care provider if you are having a blood transfusion and you have had a reaction before.
Donated blood is put into ABO and Rh groups to reduce the risk of transfusion reaction.
Before a transfusion, patient and donor blood are tested (crossmatched) to see if they are compatible with each other. A small amount of donor blood is mixed with a small amount of patient blood. The mixture is checked under a microscope for signs of antibody reaction.
Before the transfusion is given, the health care provider will usually check again to make sure you are receiving the right unit of blood.
Choat JD, Maitta RW, Tormey CA, et al. Transfusion reactions to blood and cell therapy products. In: Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Saunders Elsevier; 2012:chap 120.