Your immune system produces antibodies as proteins to combat invading substances (antigens). The blood cells that contain foreign substances like B antigens will be attacked by anti-B antibodies. The existence and quantity of anti-B antibodies in the blood can be found by using an anti-B antibody titre test. Pregnant women do this test to look for antibodies that may result in hemolytic illness in their unborn children. Additionally, this test aids in decision-making prior to a kidney transplant process. This test provides information on the need for a booster dosage in terms of vaccination. The anti-B titre also aids in determining whether an individual has been exposed to any infections.