Frozen blood plasma in storage. Plasma is the straw-coloured liquid component of blood that remains after the blood cells have been removed. It is stored at -18 degrees Celsius and can last for up to a year. Blood plasma is rich in clotting factors and is used to replace blood lost during childbirth and cardiac surgery, and to treat many types of bleeding disorders. This blood plasma, from the UK National Blood Service, is from a blood group A donor, and is additionally classed as Rhesus (Rh) D positive. This allows the plasma to be matched to compatible patients, and so avoid potentially fatal reactions by the immune system of the patient.