Blood typing is used to determine your blood group and what type of
blood or blood components you can safely receive. It is important to ensure that there is compatibility between a patient who requires a transfusion of blood or blood components and the ABO and Rh type of the unit of blood that will be transfused. A potentially fatal
transfusion reaction can occur if a unit of blood containing an ABO antigen to which a patient has an
antibody is transfused to that patient. For example, people with blood group O have both anti-A and anti-B antibodies in their blood. If a unit of blood that is group A, B, or AB is transfused to this patient, the antibodies in the patient’s blood will react with the red cells, destroying them and causing potentially serious complications.
If an Rh-negative patient is transfused with Rh-positive blood, it is likely that the patient will produce antibodies against Rh-positive blood. Although this does not cause problems for the patient during the current transfusion, a future transfusion with Rh-positive blood could result in a serious transfusion reaction.
Rh typing is especially important during pregnancy because a mother and her fetus could be incompatible. If the mother is Rh-negative but the father is Rh-positive, the fetus may be positive for the Rh antigen. As a result, the mother’s body could develop antibodies against the Rh antigen. The antibodies may cross the placenta and cause destruction of the baby’s red blood cells, resulting in a condition known as hemolytic disease of the fetus and newborn. To prevent development of Rh antibodies, an Rh-negative mother is treated with an injection of Rh immune globulin during her pregnancy and again after delivery if the baby is Rh-positive. The Rh immune globulin “masks” any Rh antigen from the fetus that the mother may be exposed to during her pregnancy and delivery and prevents her from becoming sensitized and developing antibodies against the Rh antigen.
Blood typing is also used to determine the blood group of potential donors at a collection facility. Units of blood that are collected from donors are blood typed and then appropriately labeled so that they can be used for patients that require a specific ABO group and Rh type.
ABO grouping and Rh typing are performed on all donated blood. They are also performed for all patients requiring a blood transfusion. Cases in which blood or blood products are needed for treatment may include:
Severe anemia and conditions causing anemia such as sickle-cell disease and thalassemia
surgical patients with intra-operative or post-operative bleeding
injury or trauma patients with excessive blood loss
cancer and the effects of chemotherapy
bleeding disorders such as hemophilia
All pregnant women should be tested to determine whether they are Rh negative or positive. All newborns of Rh negative moms should also be tested to determine if the mother needs to receive Rh immune globulin.
The results of blood typing will tell you if you are group A, B, AB, or O and if you are Rh negative or positive depending on what antigens are present on your red blood cells. The results will tell the physician treating you what blood or blood components will be safe for you to receive.
The results will tell a pregnant woman whether she is Rh positive or negative and whether she may be a candidate for receiving Rh immune globulin to prevent her from potentially developing antibodies against her fetus’ blood cells.
Blood typing will also tell the personnel at a collection facility what blood type you are donating and who can safely receive your blood.
