Blood typing is done prior to a blood transfusion or when classifying a person’s blood for donation. Blood typing is a fast and easy way to ensure that you receive the right kind of blood during surgery or after an injury. If you are given incompatible blood, it can lead to blood clumping, or agglutination, which can be fatal.Blood typing is especially important for pregnant women. If the mother is Rh- and the father is Rh+, the mother and child will have different blood types. In these cases, the mother needs to receive a drug called RhoGAM. This drug will keep her body from attacking the baby’s blood cells if their blood becomes mixed, which often happens during pregnancy.