Patients who have blood disorders, certain kidney problems, metabolic disorders, or autoimmune disorders need to have components of their blood removed regularly to stay healthy. This procedure is called therapeutic apheresis. In therapeutic apheresis, the part of the blood that is causing symptoms is removed, and the remaining blood is returned to the body. While it does not cure disease, apheresis can reduce symptoms and keep patients healthier and more comfortable.
Therapeutic apheresis can be used to remove the following blood components:
- Plasma, which is the clear fluid that makes up most of the blood. Often, removed plasma is replaced with donor plasma or saline to keep blood pressure stable.
- Red blood cells, which cells carry oxygen. When red blood cells are removed, they are often replaced with donor cells to maintain oxygen levels.
- White blood cells, which help fight infection. These are typically removed in patients with leukemia or patients with a high number of white blood cells.
- Platelets, which help the blood to clot. If there are too many platelets in the blood, they are removed to avoid problems with bleeding.
During the procedure, a tube is connected to a vein via a needle in the arm or, in patients who need frequent apheresis, a mainline catheter. The blood is pumped to a machine, where it spins in a centrifuge. Distinct components of blood spin to different areas on the centrifuge because of their specific characteristics, such as weight. After separation, the machine discards the targeted blood component and pumps the remaining blood back into the body.
Treatment can take several hours, and, depending on the diagnosis, may need to be repeated regularly. Apheresis is not particularly painful, but lower blood levels may cause temporary symptoms such as tingling in the fingers and toes, dizziness, or fatigue.