Why transfusion reaction

If an antibody is produced, future transfusions can be delayed because extended donor blood typing will be required to identify compatible units. O negative blood released uncrossmatched in emergencies could result in a hemolytic transfusion reaction if the patient has an alloantibody produced after a previous transfusion. Previous pregnancies expose the mother to novel paternally derived antigens. The most common alloimmunization associated with pregnancy is the exposure of maternal Rh D negative blood to fetal Rh D positive blood.

This results in the production of maternal IgG against the "D" antigen that can cross the placenta and attack fetal red blood cells, resulting in hemolytic disease of the newborn, also called erythroblastosis fetalis. RhoGAM consists of IgG anti-D antibodies that will help neutralize the antigen and prevent the mother's immune system from sensitization to the antigen, and preventing the immune response that generates the alloantibodies. The use of RhoGAM and greatly reduced the incidence of Rh anti-D erythroblastosis fetalis, and so other blood group antigens, such as Kell, may be implicated.

Prior exposure to non-self HLA antigens from WBC contamination of red cell products can result in antibodies that will render future platelet transfusions useless. If an alloantibody is detected, then RBC units may be crossmatched randomly, assuming that the alloantibody is against a "low incidence" antigen which most units will lack. Chances are, enough compatible units will be identified. If an alloantibody is directed at a "high incidence" antigen, then there will be few, if any, units available that match.

In that case, "rare" blood units lacking the antigen may be requested from a facility that stores such blood. The thawed units are washed of the glycerol, and by doing so are also depleted of plasma and leukocytes.

HLA unmatched platlets random donor platelets are likely to be destroyed readily. The process of identifying alloantibodies and finding compatible blood products is time consuming. In some cases they can be life threatening. This can be due to:. Blood transfusions are most commonly done for blood components, such as red blood cells, platelets, or plasma. Before a blood transfusion, a medical provider will draw your blood.

This sample will be sent to a laboratory for typing and crossmatching. Typing is when the lab determines blood type. Knowing your blood type is important because red blood cells contain antigens, or protein markers, corresponding to these blood types. If a laboratory gives you the wrong type of blood, your immune system will detect any foreign proteins on the red blood cells of the wrong blood type and attempt to destroy them. Blood banks have thorough testing processes to make sure blood is safe and correctly typed for use.

A doctor or nurse will stay with you while you receive the transfusion. They will check your vital signs and watch for symptoms that you may be having a reaction. In some instances, however, transfusion reactions take place days after the transfusion. You can have an allergic reaction to a blood transfusion as well. These symptoms can include hives and itching. This reaction type is often treated with antihistamines.

This reaction may occur when donor plasma contains antibodies that cause damage to the immune cells in the lungs. This lung damage results in fluid buildup in the lungs and can severely limit the ability of the lungs to supply oxygen to the body.

This reaction usually occurs within six hours of receiving blood. In rare instances, bacteria may be present in the donated blood. Giving this contaminated blood to a recipient can lead to infection, shock, and death.

A transfusion reaction can also occur if a person receives too much blood. This is known as transfusion-associated circulatory overload TACO. What Happens to Donated Blood. Blood Transfusions. Risks and Complications. Some of the most common complications in blood transfusions are listed below. Allergic Reactions Some people have allergic reactions to blood received during a transfusion, even when given the right blood type. Fever Developing a fever after a transfusion is not serious. Blood-borne Infections All donated blood is screened and tested for potential viruses, bacteria, and parasites.

All donated blood is thoroughly tested for HIV. There is a 1 in 2 million chance that donated blood will not only carry HIV but also infect a transfusion recipient. Hepatitis B and C.