What happens if a patient receives the wrong blood type?

If a patient receives a blood type that is incompatible, antibodies that the patient already has in his or her blood will attack the donor red blood cells and destroy them. This could cause fever, chills, chest or back pain, bleeding, increased heart rate, shortness of breath, rapid drop in blood pressure, and/or kidney damage. This is called an acute hemolytic reaction. A delayed hemolytic reaction can also occur, which is generally less severe or even asymptomatic, but there will still be destruction of blood cells.
Discovery Health

Blood type must be determined before blood is transfused into a patient to prevent a transfusion reaction.

When someone has type A blood (with type A antigens), their plasma has type B antibodies and vice versa. Therefore, a reaction occurs when the antigens on the red blood cells of the donor blood react with the antibodies in the recipient's plasma.

For example, if a unit of blood type A (which contains A antigens) is transfused into someone with type B (they have anti-type A antibodies in their blood), a transfusion reaction will occur.

When a transfusion reaction does occur, an antibody attaches to antigens on several red blood cells. This causes the red blood cells to clump together and plug up blood vessels. Then the cells are destroyed by the body (a process called hemolysis), releasing hemoglobin from the red blood cells into the blood. Hemoglobin is then broken down into bilirubin, which can cause jaundice.

If an emergency blood transfusion is needed and the recipient's blood type is not known, anyone can receive type O- blood. Type O- blood (which has no antigen on its surface) will not react with antibodies in the recipient's plasma. Anyone with type O- blood is called a universal donor. Those with type AB blood (which has no antibodies) are called universal recipients, because their plasma will not react with donated blood.

Continue Learning about Blood Basics

Blood Basics

Blood Basics

Our blood is a living tissue with a variety of critical functions: It delivers oxygen and nutrients to our organs, fights infections and creates blood clots, preventing us from bleeding excessively when a blood vessel is damaged. ...

The liquid part of our blood, called plasma, is key for maintaining blood pressure and supplying critical proteins for blood clotting, immunity and maintaining the correct pH balance in our body -- critical to cell function. Plasma also carries the solid part of our blood -- white blood cells, which work to destroy viruses and bacteria; red blood cells, which carry oxygen through the body; and platelets, which help clotting. Learn more about blood basics with expert advice from Sharecare.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.