Apheresis is a medical procedure that involves a blood donor receiving their blood back once some component has been extracted. The other blood components, including red blood cells, are still intact. While any part of the blood can be separated out, the most common forms of apheresis are plasmapheresis, plateletpheresis, and leukapheresis. Apheresis is usually performed either because one part of a patient's blood is causing health problems or because a donor wishes to donate one needed blood component.
When a person's blood has a high platelet count, for example, it can lead to an increase in the risk of blood clots. Plateletpheresis can be performed to remove some of the platelets and lower this risk. Other people don't have enough platelets in their blood, and those donated from others through apheresis can be transfused in to help the blood clot properly.
Almost anyone over 18 years of age can donate blood. A donor must weigh at least 110 pounds (50 kg) and must have donated blood in the last two years. The previous blood donation must have had a good blood flow, and the donor must have had no adverse reactions. Only people with certain blood types can donate specific blood components; people donating plasma, for example, must be type A, B, or AB, Rh positive or negative.
The procedure for apheresis donation is much the same as a normal blood donation. The blood will be extracted from the arm through a sterile, disposable kit that is housed in a special machine. The machine is called a cell-separator. The cell-separator removes the required components from the blood by using another machine called a centrifuge. The remaining blood is returned to the donor using the same needle.
During the procedure, citrate is added to the blood to prevent the blood from clotting while it is outside of the body. A small amount of the citrate returns to the donor. This may cause a sensation of coldness and tingling around the mouth area during the donation, but this usually quickly subsides. The citrate is broken down very quickly once it enters the bloodstream.
Apheresis is often performed when the target constituents in a patient's blood cause severe symptoms of disease, such as bleeding problems, or diseases such as cancer. This procedure has to be performed quite often. As it is an invasive procedure, it is only performed if all other means of controlling the disease have failed. It is also performed if the symptoms of a disease are so severe that there is a risk of complications or suffering while waiting for the medication to work.