yping allows the prediction of a phenotype based on the knowledge of the molecular basis of the currently known antigens. This allows a more detailed determination of the blood type and therefore a better match for transfusion, which can be crucial in particular for patients with needs for many transfusions to prevent allo-immunization.[28][29]ඉතිහාසය[සංස්කරණය]The two most significant blood group systems were discovered by Karl Landsteiner during early experiments with blood transfusion: the ABO group in 1901[30]  and in co-operation with Alexander S. Wiener the Rhesus group in 1937.[31]  Development of the Coombs test in 1945,[32]the advent of transfusion medicine, and the understanding of ABO hemolytic disease of the newborn led to discovery of more blood groups, and now 30 human blood group systems are recognized by the International Society of Blood Transfusion (ISBT),[2] and across the 30 blood groups, over 600 different blood group antigens have been found;[4] many of these a