Plasmapheresis is a process in which the liquid in the blood, or plasma, is separated from the cells. In sick people, plasma can contain antibodies that attack the immune system.

A machine removes the affected plasma and replaces it with good plasma, or a plasma substitute. This is also known as plasma exchange.

The process is similar to kidney dialysis. Plasmapheresis also can refer to the plasma donation process, where the plasma is removed and cells are returned to the body.

What Does Plasmapheresis Do?

Plasmapheresis can be used to treat a variety of autoimmune disorders, including myasthenia gravis, Guillain-Barre syndrome, and Lambert-Eaton. It can also be used to treat multiple sclerosis.

Sometimes, it is used in people who have received an organ transplant, to counter the effects of the body's natural rejection process.

In recent years, the therapy has increasingly been used to treat critically ill patients with infections and other problems.

How is Plasmapheresis Administered?

During plasmapheresis treatment or donation, patients or donors rest on a cot. A needle or catheter is placed into a vein in the crux of whichever arm has the most robust artery. In some cases, a catheter is placed in the groin or shoulder.

Replacement or returned plasma flows into the body through a second tube that is placed in the arm or foot.

Treatments can last between one and three hours. A patient can need as many as five treatments per week. Treatment frequency can vary widely from condition to condition, and also depend on a person's overall health.

According to federal regulations, a person can donate plasma up to twice a week. Donation sessions usually take about 90 minutes.

Sometimes hospitalization is required. In other cases outpatient treatment is possible.