Identification of abnormal antibodies is an important test before blood transfusion. The test is performed mainly in people who have received multiple blood transfusions, women with a history of childbirth, pregnancy, and multiple miscarriages.

The Rh blood group system is one of the two most important blood group systems involved in blood transfusion. The Rh blood group system includes Rh(+) and Rh(-), of which Rh(+) is the majority.