Blood is transfused either as whole blood (with all its parts) or, more often, as individual parts. The type of blood transfusion you need depends on your situation.
For example, if you have an illness that stops your body from properly making a part of your blood, you may need only that part to treat the illness.
Red Blood Cell Transfusions
Red blood cells are the most commonly transfused part of the blood. These cells carry oxygen from the lungs to your body's organs and tissues. They also help your body get rid of carbon dioxide and other waste products.
You may need a transfusion of red blood cells if you've lost blood due to an injury or surgery. You also may need this type of transfusion if you have severe anemia (uh-NEE-me-uh) due to disease or blood loss.
Anemia is a condition in which your blood has a lower than normal number of red blood cells. Anemia also can occur if your red blood cells don't have enough hemoglobin (HEE-muh-glow-bin).
Hemoglobin is an iron-rich protein that gives blood its red color. This protein carries oxygen from the lungs to the rest of the body.
Platelets and Clotting Factor Transfusions
Platelets and clotting factors help stop bleeding, including internal bleeding that you can't see. Some illnesses may cause your body to not make enough platelets or clotting factors. You may need regular transfusions of these parts of your blood to stay healthy.
For example, if you have hemophilia (heem-o-FILL-ee-ah), you may need a special clotting factor to replace the clotting factor you're lacking. Hemophilia is a rare, inherited bleeding disorder in which your blood doesn't clot normally.
If you have hemophilia, you may bleed for a longer time than others after an injury or accident. You also may bleed internally, especially in the joints (knees, ankles, and elbows).
Plasma is the liquid part of your blood. It's mainly water, but also contains proteins, clotting factors, hormones, vitamins, cholesterol, sugar, sodium, potassium, calcium, and more.
If you have been badly burned or have liver failure or a severe infection, you may need a plasma transfusion.