There are four components - or parts - of the blood: red blood cells, white blood cells, plasma and platelets. Blood carries things you need, like oxygen and glucose, and waste products ...

An average man will have more, usually between 4.2 and 5.7 litres. Blood serves many life-giving functions. It is composed of platelets which control clotting to stop the body bleeding out ...

The Complete Blood Count (CBC) test measures the levels of different components of blood ... the risk of cardiovascular diseases. Liver function tests (LFTs) measure the levels of enzymes and ...