Blood Transfusion Procedure
The most common blood types are A, B, AB, and O. In addition, your blood is either Rh-positive or Rh-negative. If, for example, your blood is B positive, this means that you have type B blood that is Rh-positive.
The blood you receive during a transfusion has to be appropriate for your blood type. If it isn’t, the antibodies (protein in the immune system that destroys or helps destroy foreign substances) in your blood could attack the new blood, which can cause a serious reaction or even be life threatening. It’s less critical to match your blood type to the donor’s blood type if you are receiving a platelet or cryoprecipitate transfusion, although labs usually try to match blood type in these cases if possible.
No matter what type of blood you have, you can safely be given type O blood. People with type O blood are called “universal donors.” If you have type AB blood, you are known as a “universal recipient” because you can safely be given any type of blood.
If your blood is Rh-positive, you can receive Rh-positive or Rh-negative blood. But if you have Rh-negative blood, only Rh-negative blood is safe for you.
Sources of Donated Blood
Blood banks collect blood from volunteers who give, or donate, some of their blood. Blood banks test all donated blood to find out if it has any viruses or other infectious agents that might make you sick. They also test donated blood to find out its type (A, B, AB, or O) and whether it is Rh-positive or Rh-negative.
In some cases, it might be possible for you to donate blood before surgery that can be given to you during surgery. This is known as autologous donation. If your doctor agrees, you will donate your blood up to 6 weeks before your surgery. Another option in certain situations is for the surgeon to collect your blood during the surgery. The surgeon then transfuses your blood back to your body after the operation is over. The advantage of autologous blood donation is that the blood is a perfect match for you. Of course, if your blood is already low, you cannot donate your own blood.
Friends and family members can also donate blood specifically for you, if your doctor agrees. This is known as directed donation. Their blood must be checked carefully to make sure that it is a suitable match for you. If it’s not, the blood might be given to another patient. There is no scientific evidence that transfusions from directed donations are safer or better than transfusions of blood from blood banks.
Before the Transfusion
Before your transfusion, a technician will test your blood to find out your blood type. The technician will mix a sample of your blood with a sample from a blood donor. If the blood cells clump together, this means that your blood is not compatible with the donor’s blood, and another sample will be chosen. If the blood cells don’t clump together, the donor’s blood is a good match for you and you can safely receive a transfusion of this blood. This procedure is known as cross-matching.
If you have allergies or you have had an allergic reaction during a blood transfusion in the past, your doctor might prescribe a medication to prevent an allergic reaction to the donated blood. For example, the doctor might prescribe Tylenol® (acetaminophen) or Benadryl® (diphenhydramine). You will probably take this medicine a half hour or so before the transfusion.
You probably won’t have to make any changes to your diet or activities to prepare for a blood transfusion.
You will probably have your transfusion in the doctor’s office or a hospital (either in the outpatient center or in your hospital room). In rare cases, a transfusion can be done in your home. You will probably receive a transfusion of one or more components of blood, such as red blood cells, platelets, or plasma; transfusions of whole blood are rare.
A technician will hang a bag containing the blood product from a pole. The technician will insert an intravenous (IV) line, or narrow tube into a blood vessel, most likely in your arm. The healthy blood from a donor will drip from the bag through this line and into your vein. The procedure usually takes about 1 to 2 hours, depending on what blood component(s) you are receiving. Red blood cell transfusions take slightly longer than transfusions of other blood components.
A nurse will keep an eye on you during the transfusion procedure to make sure that you don’t have an allergic reaction or other side effect. The nurse will check your vital signs—including your temperature, blood pressure, and heart rate—before, during, and after the transfusion.
You can eat or drink during the procedure. You can also get up and walk around. But if you do move around, you need to move carefully and slowly so that the needle does not come loose.
Once the bag is empty, the technician or nurse will remove the needle from your arm. The place where the IV was inserted might be sore or bruised for a few days. You can do your normal activities as soon as the procedure is over.
This content was last reviewed
August 15, 2010 by Dr. Reshma L. Mahtani.