This is an agglutination test used to determine the blood group (ABO) as well as Rh factor. This test is useful for the screening of blood for transfusion purposes, for typing of pregnant mother and baby to cope with complications of hemolytic diseases. Similarly, determination of Rh factor is important in prenatal and postnatal patients. This test is also recommended in case of organ donor as HLA as well as ABO/Rh compatibility is critical. Other situations when this test is widely used is in diseases like anemia, thalassemia and hemophilia and trauma or accidental blood loss.