Red blood cell bind oxygen and is responsible for the red color of the cells and the blood. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological cell function such as deformability and stability while traversing the circulatory system and specifically the capillary network. In humans, mature red blood cells are flexible and oval biconcave disks. They lack a cell nucleus and most organelles, in order to accommodate maximum space for hemoglobin; they can be viewed as sacks of hemoglobin, with a plasma membrane as the sack. Approximately 2.4 million new erythrocytes are produced per
Packed red blood cells as anaphylaxis, red blood cell breakdown, infection, volume overload, and lung injury. With current preparation methods in the developed world the risk of viral infections such as hepatitis C and HIV/AIDS are less than one in a million. However, the risks of infection are higher in low income countries. Packed red blood cells are produced from whole blood or by apheresis. They typically last for three to six weeks. The widespread use of packed red blood cells began in the 1960s. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in