Blood – that magical, mystical fluid of life! It is described as such in the Bible (King James Version) in Leviticus 17:11: "For the life of the flesh is in the blood…"

Man has been fascinated by blood since the dawn of time, and it was the Ancient Greeks, most famously Hippocrates (c. 460 BC – 370 BC) and Aristotle (c. 384 BC – 322 BC), who are credited with positing  that the body was made up of four "humours" or liquids - phlegm, blood, yellow bile and black bile. It was thought that illnesses were due to an imbalance of these humours, and that treating disease was largely a matter of restoring their equilibrium. 

These teachings continued for centuries and dominated the practice of medicine in the Middle Ages, when physicians strove to maintain the balance in the humours in a variety of ways, including the use of the right foods, herbs, drugs or procedures. Each humour had different elements and qualities associated with it, and one of these for blood was heat. It was believed, therefore, that if a person had a fever he or she must perforce have too much blood, and thus that patient was cut (sometimes leeches were applied instead) and bled!

When English physician William Harvey (1578-1657) in 1628 described how blood circulated around the body, pumped by the heart, physicians started to experiment with blood transfusions – between animals at first, but then in humans, whom they transfused initially with the blood of animals like sheep and cows. By the early 1800s human-to-human transfusions began, though the failure rate was high, and it was not until Austrian physician Karl Landsteiner (1868 - 1943) discovered the main blood groups – A, B and O (later AB and Rh) that the way was paved for the development of modern transfusion practices.

The term "blood bank" was allegedly coined by Dr Bernard Fantus (1874 - 1940), a Hungarian-American physician who was successful in preserving blood in his "Blood Preservation Laboratory" at the Cook County Hospital in Chicago, USA, which he renamed before its launch to "Cook County Hospital Blood Bank" in March 1937. By the next year, a recognized blood bank was established in England, and Jamaica had a functional blood bank from at least 1946, sited in the then Bacteriological Laboratory on North Street in Kingston. Our modern blood bank – The National Blood Transfusion Service (NBTS) on Slipe Pen Road, Kingston, was established in 1957. Testing of blood is centralized and is done only at the NBTS, though the components (see below) are also prepared at the Cornwall Regional Hospital and the University Hospital of the West Indies.

Blood and its use 
Many people appear to think that blood is always used whole as a complete unit (approx 500 ml or 1 pint).  Whole blood is usually only used as such for the replacement of blood volume and red cells when there is massive blood loss (usually > 40% of one's blood volume).

For more efficient use of this valuable and scarce commodity, whole blood is usually separated into its components: packed red cells, platelet concentrate, fresh frozen plasma and cryoprecipitate.

• Packed red cells – 300 ml unit: used in acute or chronic anaemic states, e.g. patients undergoing surgery, trauma in motor vehicle accidents, gunshot wounds, kidney failure, chemotherapy patients, etc.  These cells can be stored safely for 35 days and demand is always greater than supply.