Blood Supply

Blood supply refers to the blood resources in blood banks and hospitals that are critical to the health care community. The blood supply consists of donated blood units (in pints) that are used to replace blood lost during surgery or from trauma.

Blood transfusions were attempted as early as 1667 when Jean-Baptiste Denis, a French physician, transfused 12 fl oz (355 ml) of lamb's blood into a 15-year-old male patient. While Denis's subject improved immediately, later attempts to transfuse blood met with mixed results. Prior to the end of the nineteenth century, some patients who received blood from another person improved while others died quickly. In 1900, Austrian physician Karl Landsteiner discovered the four types of human blood, A, B, O, and AB, and the rules that govern their compatibility. Type O can be given to any recipient and is called the universal donor. Type A can be given to type A and AB recipients, and type B to type B and AB recipients. Transfusing blood of a type not compatible with the patient's blood can be fatal.