What is a blood transfusion?
Blood transfusion is a medical treatment that replaces blood lost through injury, surgery, or disease. The blood goes through a tube from a bag to an intravenous (IV) catheter and into your vein.
When is a blood transfusion needed?
You may need a blood transfusion if you lose too much blood, such as through:
- Injury or major surgery.
- An illness that causes bleeding, such as a Reference bleeding ulcer Opens New Window.
- An illness that destroys blood cells, such as Reference hemolytic anemia Opens New Window or Reference thrombocytopenia Opens New Window.
If you have an illness in which your Reference bone marrow Opens New Window doesn't make enough blood, such as Reference aplastic anemia Opens New Window, you may need transfusions. Some diseases, such as Reference hemophilia Opens New Window, prevent your body from making a needed blood component. Components are the different parts of blood, such as red blood cells, plasma, and platelets. You may need transfusions or injections of the missing blood component to help treat these diseases.
Is a blood transfusion safe?
Blood used for transfusions in the United States is very safe and generally free from disease. Donated blood is carefully tested. It is very rare to get a disease through a blood transfusion.
Getting the wrong blood type by accident is the main risk in a blood transfusion, but it is rare. Getting the wrong blood type happens in about 1 out of 14,000 transfusions.Reference 1 Transfusion with the wrong blood type can cause a severe reaction that may be life-threatening, but this is very rare.Reference 2
Some people bank their own blood a few weeks before they have surgery. If they need a transfusion during surgery, they can receive their own banked blood. This reduces the risk of disease and transfusion reaction from donated blood.
If you have many blood transfusions, you are more likely to have problems from Reference immune system Opens New Window reactions. A reaction happens when your body rejects the new blood and tries to attack parts of it. But tests can help avoid this. Before you get a blood transfusion, your blood is tested to find out your blood type. And the blood you will get in the transfusion is tested to make sure it matches your blood.
You may have a mild allergic reaction even if you get the correct blood type. Signs of a reaction include:
- A fever.
- Shortness of breath.
- A fast heart rate.
- Low blood pressure.
A mild reaction can be scary, but it rarely is dangerous if it’s treated quickly.
What are blood types, and why are they important?
The most important blood type classification systems are the ABO system and the Rh system. A, B, AB, and O are the Reference blood types Opens New Window in the ABO system. Each type of blood in the ABO system also has a positive or negative Reference Rh factor Opens New Window. For example, if you have "A+ blood," it means your blood is type A in the ABO system and your Rh factor is positive.
If you get blood in a transfusion that isn't the right type, you may have a transfusion reaction. A mild transfusion reaction rarely is dangerous, but you must get treatment quickly. A severe transfusion reaction can be deadly.
How is blood collected?
Blood banks collect blood from volunteer donors. Before they donate, volunteers must answer questions about their current health, health history, and any diseases they may have been exposed to through travel to foreign countries, sexual behavior, or drug use. Only people who pass this survey are allowed to donate blood.
Donated blood is then carefully tested for certain diseases and to find out the blood type. If there is any chance that the blood may not be safe to use, it is thrown away.
Most blood that passes the tests is then split into its components and sent out for use.
Blood and its components can be stored or used for only a short time before they must be thrown away. This is why blood banks are always looking for donors.
|By:||Reference Healthwise Staff||Last Revised: Reference October 27, 2011|
|Medical Review:||Reference E. Gregory Thompson, MD - Internal Medicine
Reference Brian Leber, MDCM, FRCPC - Hematology