Plasmapheresis consists in taking blood from a subject, with immediate separation of the liquid component from the corpuscular one (red blood cells, white blood cells and thrombocytes); all thanks to the help of an automated mechanical separator, which divides the two components by centrifugation.
Plasmapheresis is a fundamental procedure for the production of so-called plasma-derived drugs. In the liquid component of the blood, in fact, we find remarkable quantities of proteins, therefore antibodies (immunoglobulins), peptide hormones, coagulation factors and proteins necessary for the transport of insoluble substances. Respiratory gases and all the various nutrients (glucose, vitamins, amino acids, fatty acids, etc.) are also present in the plasma.
The protein component of plasma is fundamental for the production of drugs to be destined to patients with specific plasma substance deficiencies; subjects affected by hemophilia A and B, for example, have a strong deficiency of coagulation factors VIII or IX, which can be extracted and purified from the donor's plasma and then administered to the recipient.
Furthermore, the "whole" plasma can be administered as such to patients suffering from particular pathologies, which require their replacement due to an excess of anomalous antibodies or other reasons.
Leaving the sphere of donations, there is also a therapeutic plasmapheresis, aimed at the simple removal of excess plasma molecules (bilirubin, LDL etc.). In these cases, the most correct term is given by the name of the isolated pathogenic molecule, followed by the term apheresis (from "afero", take away).
Questions and answers on plasmapheresis (plasma donation)
HOW MUCH PLASMA IS PICKED UP? Normally, 500 ml of plasma are taken during plasmapheresis. The donation can be made once every three months but also once every 14 days; according to the law in force, it is in fact possible to make up to 20 donations of plasma of 500ml per year.
IS PLASMAPHERESIS DANGEROUS FOR DONOR HEALTH? The plasma volume is immediately compensated through the integration of oral fluids (drinking before and after the collection), or by infusion of physiological solutions during the return of the cells.
The lost protein components are instead replaced within three days (the coagulation factors and the fibrinogen are recovered in 24 hours, the immunoglobulins in 48 and the complement c3 within 72 hours).
WHICH CHARACTERISTICS MUST THE DONOR HAVE? To be suitable for plasmapheresis, the donor must weigh more than 50 kg, be aged between 18 and 55-60 years, and respond to a series of requirements, such as proteins greater than 6 grams / dL, higher platelet number at 200, 000 / mL, and hemoglobin values above 12.5 g / dL, if male, or 11.5 g / dL if female. Although plasma is tested for the presence of infectious diseases (viral hepatitis, AIDS, etc.) it is important that the donor does not have risky sexual relations. Furthermore it is fundamental to declare to the doctor the assumption of any drug, in order to evaluate the possibility of a possible postponement of the donation.
We remind you that the donor has the right to a paid day of work rest (for employees) and to free periodic medical and laboratory checks (hemoglobin, transaminases, azotemia, triglyceridemia, glycaemia, ferritinemia, cholesterol, hepatitis B and C, AIDS) and all those you like).
HOW MUCH DO THE PLASMAPHERES PROCEDURE LAST? The duration of the donation increases as the hematocrit increases and the blood flow guaranteed by the vein is reduced. On average, it takes 40 minutes, with fluctuations ranging from 30 to 60 minutes based on the aforementioned factors. During this time, from 2 to 3 cycles are completed consisting of two separate phases, one of which is collection, separation and accumulation, and one of re-infusion of the corpuscular component.
WHAT DOES ACD-A MEAN? It is a solution of citric acid and dextrose, used as an anticoagulant during plasmapheresis (ACD-A = Anticoagulant Citrate Dextrose Solution A ). We are talking about a safe drug, which can cause only a temporary decrease in calcemia, signaled by the appearance of tingling in the lips. If this symptom does not resolve within a few minutes, it is sufficient to take a calcium tablet to make the continuation of plasmapheresis more comfortable.
