Pheresis

The term 'Pheresis' is of Greek origin and it means 'to take away' or 'separate'. Pheresis is a special kind of blood donation. The specific components of blood namely the plasma, erythrocytes, platelets, granulocytes, agranulocytes are separated. In this procedure, the blood component needed to diagnose a suspected abnormality or treat a known disease is separated and the remaining blood is returned to the donor. Pheresis can also be described as a blood purification process.

During pheresis, whole blood is collected from one arm of the donor and this goes into a machine called 'cell separator'. The blood is spun in the machine and components separated and after the desired component is collected into a special bag, the red cells and other components are returned to the donor. As most blood is returned to the donor, pheresis facilitates a donor to donate more of a specific component. There are two main types of pheresis. One is removal of platelets - platelet pheresis and removal of plasma - plasmapheresis.

Plateletpheresis: This is especially used in patients who have leukemia or aplastic anemia and are receiving chemotherapy. They need platelets as cancer and cancer treatments can deplete the body of platelets. Platelets are necessary to prevent potentially fatal bleeding problems. Platelet is a very precious component of blood that can be stored only for five days and only about one tablespoon of platelet can be collected from one unit.

Plasmapheresis: Otherwise known as therapeutic plasma exchange, in plasmapheresis, the cells from the straw colored liquid portion of the blood which contains the clotting factors, infection fighting antibodies and other proteins are removed. Plasma is necessary to regulate blood pressure and maintain the mineral balance in the body. Fresh frozen plasma is also administered to control disseminated intravascular coagulation.

A flexible tube is inserted into the donor's arm. Blood is slowly drawn into a sophisticated machine which separates various components of blood. Each pheresis donation is typed and marked for a specific patient. Both plasmapheresis and plateletpheresis can be conducted in a hospital or blood donation center. There are certain preparatory procedures that a donor needs to follow before undergoing pheresis. He/she should get a good night's sleep, eat a balanced diet, drink plenty of caffeine-free liquids. A donor is also advised not to consume aspirin within 72 hours or ibuprofen within 24 hours before undergoing pheresis. After the donation, the pheresis donor may feel tired for a few hours. The donor should not plan on driving home after the procedure. Heavy lifting or strenuous exercise need be avoided until the following day.