Global Perspectives on Obstetric Anesthesia: Challenges and Priorities for Advancing Maternal Health

There are several different compatibility tests that the blood bank performs in order to ensure patient safety with blood transfusions and to prevent hemolytic transfusion reactions due to antibody-antigen interaction. Blood typing involves combining recipient RBCs with different serums containing anti-A, anti-B, and anti-D antibodies in order to determine the recipient blood type. A crossmatch involves mixing donor RBCs with recipient serum in order to evaluate for a hemolytic reaction. Crossmatching blood is a three-step process that takes approximately 45-60 minutes. The first step examines the immediate phase and confirms the blood type by detecting ABO antibodies as well as other antibodies including MN, P, and Lewis systems. The second phase includes taking the results of the first phase at 37 oC and incubating them in albumin or low-ionic strength salt solution to detect incomplete antibodies primarily in the Rh system. The final phase is an indirect antiglobulin test to detect the majority of the incomplete antibodies Rh, Kell, Kidd, and Duffy blood group systems. Antibody screening involves mixing recipient serum with RBCs that contain specific numbers of RBC antigens. In addition, antibody screening is performed shortly after blood donation on donor serum to antibodies in donor serum from mixing with recipient serum during transfusions. In emergency situations there may not be enough time to complete a type and crossmatch. In order to most likely avoid a serious hemolytic transfusion reaction, a type and partial crossmatch should be completed if time permits. The partial crossmatch involves mixing recipient serum with donor RBCs at room temperature, spinning the blood in a centrifuge, and evaluating for the presence of agglutination. This process takes a couple of minutes and helps to prevent a serious hemolytic transfusion reaction.