According to the World Health Organization, at least 90 million whole blood units are received from donors around the world annually. Despite this large amount of blood, developing countries experience an inadequate supply of blood for transfusions, and there is a constant concern over the spread of infectious diseases using donated blood. In response to these issues, red blood cells have been generated ex vivo from hematopoietic stem cells derived from the bone marrow or peripheral blood. To further expand this approach, the United States Department of Defense launched a research program called the Blood Pharming program in 2007 to determine the effectiveness of this cell-based approach to manufacturing red blood cells.