Key Points

• A blood transfusion is a safe procedure in which blood is given to you through an intravenous (IV) line in one of your blood vessels.
• Blood is transfused either as whole blood (with all its parts) or, more often, as individual parts. The individual parts include red blood cells, platelets, clotting factors, and plasma.
• Every person has one of the following blood types: A, B, AB, or O. Also, every person's blood is either Rh-positive or Rh-negative. The blood used in a transfusion must work with your blood type. If it doesn't, antibodies (proteins) in your blood attack the new blood and make you sick.
• Blood banks collect, test, and store blood. They carefully screen all donated blood so the right blood type is available for your transfusion.
• Each year, almost 5 million Americans need blood transfusions. This procedure is used for people of all ages.
• Many people who have surgery need blood transfusions because they lose blood during the operation. People who have serious injuries also may need blood transfusions to replace lost blood. Some people need blood transfusions because they have illnesses that prevent their bodies from properly making blood or parts of blood.
• Before a blood transfusion, a technician will test your blood to find out what blood type you have. Your doctor may prescribe medicine to prevent an allergic reaction. Most patients don't need to change their diets or activities before or after a blood transfusion.
• When there isn't time to test for blood type (such as during an emergency), type O blood is used. Type O is safe for almost everyone.
• Blood transfusions usually take place in either a doctor's office or a hospital. The transfusion takes 1 to 4 hours. The time depends on how much blood you need and what part of the blood you receive.
• After a blood transfusion, your vital signs are checked. You may need blood tests that show how your body is reacting to the transfusion.
• Most blood transfusions go smoothly. However, mild problems and, very rarely, serious problems can occur. They include allergic reactions, transmission of viruses and infectious diseases, fever, iron overload, lung injury, reactions from receiving the wrong blood type, and immune system problems.
• There is currently no man-made alternative to human blood. However, researchers have developed medicines that do the job of some blood parts. Research is ongoing to find a way to make blood.