Red blood cell (which he later renamed to O). Landsteiner described the regular patterns in which reactions occurred when serum was mixed with red blood cells, thus identifying compatible and conflicting combinations between these blood groups. A year later Alfred von Decastello and Adriano Sturli, two colleagues of Landsteiner, identified a fourth blood group—AB. In 1959, by use of X-ray crystallography, Dr. Max Perutz was able to unravel the structure of hemoglobin, the red blood cell protein that carries oxygen. The oldest intact red blood cells ever discovered were found in Ötzi the Iceman, a natural mummy of a man who died around
Packed red blood cells they can be frozen for up to 10 years. The cells are separated from the fluid portion of the blood after it is collected from a donor, or during the collection process in the case of apheresis. The product is then sometimes modified after collection to meet specific patient requirements. The product is typically abbreviated RBC, pRBC, PRBC, and sometimes StRBC or even LRBC (the latter being to indicate those that have been leukoreduced, which is now true for the vast majority of RBC units). The name "Red Blood Cells" with initial capitals indicates a standardized blood product in the