The Rh (Rhesus factor) antibody Titres test is performed to determine the Rh negativity in a persons blood serum. The type and quantity of the antibodies in the blood serum can be determined. During early stages of pregnancy, this test proves fruitful in knowing whether the mother is Rh negative. Later, the new born may also be tested to determine whether the Rh negativity has passed from the mother to the baby through the placenta. Problem arises when Rh negative blood comes in contact with Rh positive blood. In such a case, the Rh antibody Titres test is done to protect against Rh sensitization. The Rh antibody Titres test is usually ordered in case of an impending booster shot, recent or past infection, and to determine any autoimmune disorder.