Plasmapheresis is a medical procedure in which blood is removed from the body and spun in a centrifuge to filter out the plasma. The red blood cells are returned to the body, and the plasma may be treated and reintroduced, or replaced, depending on the condition which the plasmapheresis is designed to treat. This technique is also used by blood banks for plasma donors, in which case the filtered plasma is tested to make sure that it is safe, and then packaged for use by hospitals.
In the popular American television series House, it seems like Dr. House is constantly ordering plasmapheresis for his patients. In fact, this treatment is relatively rarely used, especially in the United States, with most doctors using it specifically for the treatment of autoimmune conditions. Plasmapheresis is also not an effective therapy on its own, as it must be combined with more long-term treatments which are designed to address the issue causing problems with the blood plasma in the first place.
In a typical plasmapheresis session, a venous catheter is placed in the patient, and then hooked up to a plasmapheresis machine. As the blood is pulled out, it is treated with an anticlotting agent to keep it from clotting up outside the body. After being spun, the red blood cells are returned. In some cases, the plasma is treated and then returned, and in other instances it may be discarded and replaced with fresh plasma or a stand-in of some form. If the plasma is being collected for donation, it is pulled off into sterile packaging.
As a general rule, plasmapheresis is not painful, but it can be uncomfortable, depending on the type of plasmapheresis being used to treat the patient. Like any medical treatment, it also has potential side effects and complications, of which the most common is an infection at the site of the catheter. A doctor will generally discuss the reasons for recommending plasmapheresis treatment, along with the potential risks, when discussing treatment options with a patient.
People who wish to donate plasma during a blood drive should be prepared for a more lengthy sit than would be required to donate blood. However, the advantage of donating plasma is that your body recovers more quickly. Within 48 hours, the body should be returned to normal, and one could potentially donate again. Not all blood banks have the facilities to handle plasmapheresis at mobile blood drives, so it is a good idea to call ahead if you only want to donate plasma.