Plasmapheresis (from the Greek plasma, something molded, and apheresis, taking away) is the removal of (components of) blood plasma from the circulation. It is used as a therapy in particular diseases, and it is also a method by which blood donors donate only plasma, with remaining red cells and platelets returned to their circulatory systems, allowing up to twice weekly plasma donations.

Indication

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An important use of plasmapheresis is in the therapy of autoimmune disorders, where the symptoms are so catastrophic that medical therapy is insufficient in controlling the symptoms. Plasmapheresis clears antibodies from circulation.

Other uses are the removal of blood proteins where these are overly abundant and cause hyperviscosity syndrome.

Examples of diseases that can be treated with plasmapheresis:

• Guillain-Barré syndrome
• Chronic inflammatory demyelinating polyneuropathy
• Goodpasture's syndrome
• Hyperviscosity syndromes:
  • Cryoglobulinemia
  • Paraproteinemia
  • Waldenström macroglobulinemia
• Myasthenia gravis
• Thrombotic thrombocytopenic purpura (TTP)
• Wegener's granulomatosis

Donation procedure

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After signing in at the donor center, a small amount of blood is drawn from a finger. This blood is analyzed for hematocrit and protein levels. The donor's weight is also taken. If these levels are sufficient, then the donor proceeds to the next step.

After the initial blood draw, the donor is then taken to a small, private room, and is asked a variety of health-related questions. These questions serve to screen out anyone whose blood may have been exposed to any pathogen that makes their plasma dangerous to the recipient. Such questions include whether the donor has been exposed to HIV, hepatitis, and whether the donor has any kind of infection. An inventory of current prescribed medications is also taken.

After the screening, further vital signs are taken, including temperature, pulse, and blood pressure. The donor's values for these vital signs must be within acceptable limits for the donation process to proceed.

After vital signs, the next step is the actual donation process. The donor rests in a reclining position on a large chair. A blood pressure cuff is attached and the phlebotomist begins to prep the needle site. A probe is used to mark the location of a suitable vein, inline and above the elbow. Then a relatively large bore needle is inserted, and the plasmapheresis machine begins the donation cycle. During this cycle, the donor must periodically squeeze their hand to encourage proper blood flow. Plasma is alternately removed and reinjected; only a small amount is removed during the various alternating cycles. During this initial stage, the machine will also analyze the blood's lipid content and determine if it is in an acceptable range.

After approximately 880 milliliters of plasma have been donated, the process ends. The plasma bottle is removed from the machine, and a bolus of saline solution is then injected into the donor, restoring fluid lost during donation.

The donation process takes about one hour, from the time of needle insertion to final wrapping of the wound.

Blood products | Medical treatments | Transfusion medicine

Plasmapherese | Plasmaphérèse | plasmaferese | Plazmafereza | اِسْتِخْراج بلازما | 血浆取出法