Reasons your doctor may order a blood transfusion
There are several reasons why you may require a blood transfusion. They include:
- You have experienced a sudden or gradual loss of blood because of surgery, trauma or medical condition
- Your body does not make enough blood because of chemotherapy or diseases that cause the bone marrow to fail
- Your body destroys the red blood cells for various reasons
Several different components of blood can be transfused into an adult. Red blood cells are the most common type of blood product transfusion. If your healthcare provider has decided you might need a transfusion of blood, or blood products, he or she will explain the reasons for the transfusion, as well as the risks, benefits and alternatives to transfusion.
Overview of Blood
Blood can be broken down into different parts that perform special roles in the body. Human blood is made of fluid called plasma. The plasma carries red and white blood cells and platelets. Each part of the blood has special functions. The cells are made in the bone marrow. The bone marrow is the soft, spongy material in the center of the bones that produces about 95 percent of the body's blood cells.
What are red blood cells?
Red blood cells carry oxygen from the lungs to other body organs and carry carbon dioxide back to the lungs. A certain number of these cells is needed for the body to function. Bleeding due to trauma, surgery or disease may cause a low red blood cell count. A low red blood cell count may result in not enough oxygen to the organs.
What are white blood cells?
White blood cells fight infections by destroying bacteria, viruses and other germs. White blood cells are rarely transfused. They are usually reserved as a temporary measure for people who have a low white cell count and severe infection that is not responsive to antibiotic therapy.
What are platelets?
Platelets help control bleeding by making clots in blood vessels opened by injury or surgery. The body may not be able to make enough platelets because of bone marrow disorders, increased destruction of platelets, or medications, such as chemotherapy. Platelets may be transfused before a procedure to prevent bleeding in a person with a low platelet count.
What is plasma?
Plasma carries the blood cells throughout the body and contains protein. Some of the proteins help the blood to clot. Plasma or fresh frozen plasma can be transfused in people who have a severe deficiency of certain clotting components of the blood or to restore volume.
Types of blood donation
Allogeneic donor (volunteer donation)The blood used at most hospitals is from volunteer donors. Donors are not paid for donating blood or blood products. Each blood donor must answer medical history questions and be given a limited physical examination before being accepted as a donor. If a person is considered high-risk for infection or problems, he or she is not accepted as a blood donor. This blood can be used later for anyone in the population.
Directed donor (family or friend donation)Family and friends can have their blood tested for compatibility and donate blood for the patient before the surgery. This needs to be done at least seven days in advance. This blood is reserved at the time of donation for the transfusion of a specific patient at a later date. This type of donation is not any safer than volunteer donation, so the blood must be tested for safety and compatibility just like volunteer donations. This blood must be donated within a month of the surgery and should be donated in a person’s name, as opposed to volunteer donation, so the blood can be released for someone else if it is not used.
Autologous donor (self-donated)An autologous blood donation is not performed much anymore. For a planned surgery, a person would donate his or her own blood up to six weeks before surgery. Most patients who are healthy enough to donate their own blood will not require transfusion. Approximately 50 percent of these donations will be thrown away since they can only be used by the donor. Many people who donate blood prior to surgery still receive blood from volunteer donors. This is because your body needs time to recover after you donate your blood. Giving blood before surgery can cause you to be anemic going into the surgery, which puts you at risk for receiving a volunteer blood transfusion even though you donated your own blood. Although some think self-donated blood is safer, you can have a fatal reaction upon transfusion of your own blood.
Tests performed on blood
The donated blood is tested for infections such as hepatitis viruses B and C, HIV (the virus that causes AIDS), human T-lymphotropic viruses (HTLV) I and II, syphilis, Chagas disease, and West Nile virus. These tests decrease the chances of transfusion-related infections. If the tested blood is found to be unsafe, it is destroyed.
Matching your blood type
Red blood cells are divided into four types: A, B, AB and O. Red blood cells also have Rh types: positive (+) and negative (-). Other non-red cell products are matched a little differently. You can only receive blood products that are compatible with or match your blood type. This minimizes the risk of a hemolytic transfusion reaction. The more transfusion you receive, the more difficult it is to match your blood.
Blood storage after donation
Blood collected from a donor is stored in sterile bags. Red blood cells are stored in the refrigerator and are good for 42 days. Platelets are stored at room temperature and are good for five days. Plasma is stored in the freezer and is good for one year. It can be thawed about 30 minutes prior to use. The bags are used once and then thrown away. Before blood is given to you, it is matched with your own blood type to make sure it is compatible.
Risks associated with a blood transfusion
A blood transfusion is a tissue transplant from another person. It’s expected that some type of reaction may occur. Except for self-donated blood, all donated blood is tested and processed to reduce the chance of virus transmission. But it can never be said that the blood is 100 percent safe because virus transmission is not the only type of transfusion reaction that can occur.