How Does the Procedure Work?
Receiving a blood transfusion is a relatively simple procedure which does not require anesthesia or special patient preparation. When a physician determines that you might need a transfusion, a health professional collects a small blood sample for pre-transfusion testing. This blood sample is carefully labeled to identify you as the patient from whom it was collected.

If you are receiving care at a hospital in King County, your blood sample is sent to our laboratory where tests are performed to ensure selection of compatible donor blood. After testing, which generally requires about an hour, compatible blood is delivered to the location where you will receive your transfusion. In hospitals outside King County, compatibility testing is performed in the hospital's lab. Before transfusing the blood, a nurse or physician will confirm that you are receiving the blood, or blood component, matched specifically for you.

The transfusion of a unit of blood generally takes one to three hours. Most commonly, the blood is transfused (given) through a needle placed in a vein in your arm while you are awake. However, if the blood is needed during surgery, you will be under anesthesia and may be unaware of the process. The procedure is nearly painless and usually requires only restricted arm movement to avoid dislodging the needle.