Stock Photo - BLOOD GROUP Photo essay from laboratory. Determination of blood group ABO on plate. Research of erythrocyte antigens ABO grouping. Here, mix of each serum drops placed aside. There is an agglutination red blood cells with the anti_B and anti_AB serum but not with anti_A serum : so the patient is group B. A drop of blood of the patient is placed with serums containing antibodies directed again antigens A blue, B yellow, A et B colorless. An agglutination of red corpuscles then indicates the blood group of the patient. This research erythrocyte antigens ABO grouping must necessarily be validated by the research of antibodies in the serum, and be made twice independently.