Antibody Screen

The antibody screen. This test is performed as part of routine pretransfusion testing for blood recipients. Its purpose is to detect antibodies against non-ABO antigens (alloantibodies) that could be incompatible with donor red blood cells (RBCs). Antibodies to non-ABO antigens may develop in anyone who has been exposed to RBC antigens different from their own through pregnancy or transfusion. The antibody screen is performed by incubating the patient’s plasma/serum at 37°C (98.6°F) with a two- or three-donor red cell panel of well-characterized, blood group O, “reagent” RBCs expressing combinations of commonly encountered, clinically significant RBC antigens. Antihuman antiglobulin (AHG) is added to enhance IgG antibody agglutination. Since IgG is a monomer, it is necessary to add AHG to bind enough red cells together to cause agglutination visible to the naked eye. Antibody screening can be performed manually or using an automated system, in liquid or solid phase. It can also be performed with enhancement media such as albumin, low ionic strength saline (LlSS), or polyethylene glycol (PEG). These enhancements may reduce the required incubation time, thus shortening the time required for completion of testing and may also enhance the sensitivity of the antibody screen. The efficiency of the antibody screen in preventing incompatible blood transfusions is greater than 99.9% (the crossmatch that typically follows the screen is designed to detect the remainder). If the screen is positive, the specificity of the antibodies present in patient serum should be identified before blood transfusion. Learn more here.

2014 Guidelines for pre-transfusion compatibility procedures in blood transfusion laboratories. British Committee for Standards in Haematology: