Patients require blood type tests primarily to determine their eligibility for blood transfusions and donations. Blood cells have differing combinations of antigens and antibodies. These combinations are categorized in the ABO system.
Rh factor testing is more important during pregnancy. During your first prenatal visit, patients will typically undergo this test. A baby can inherit the Rh factor from either parent. If the mother is Rh negative and the baby is Rh positive, there is an increased risk for complications, which may require additional testing and proactive measures.