Karl Landsteiner (1868-1943): originator of ABO blood classification.

243 I magine practising medicine without access to blood transfusions. It was Karl Landsteiner, a 1930 Nobel laureate, who classified human blood into groups based on the presence of naturally occurring agglutinating antibodies, and whose findings eventually established safe transfusion procedures. Prior to his discovery, patients in need of blood received transfusions from animals such as sheep or randomly selected human donors – usually with disastrous consequences. Landsteiner’s discovery literally saved millions of human lives.