how long before blood transfusion works
Blood transfusions are done to replace blood lost during surgery or due to a serious injury. A transfusion also may be done if your body can't make blood properly because of an illness. During a blood transfusion, a small needle is used to insert an IV line into one of your blood vessels. Through this line, you receive healthy blood. The procedure usually takes 1 to 4 hours, depending on how much blood you need. Blood transfusions are very common. Each year, almost 5 million Americans need a blood transfusion.