Stock Photo: BLOOD GROUP. BLOOD GROUP Photo essay from laboratory. Determination of blood group ABO on plate. Research of erythrocyte antigens ABO grouping. Here, mix of each drop of the patient blood with each serum drops placed aside. There is an agglutination red blood cells with the anti_B serum : so the patient is either group B or AB. 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