Apheresis

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Apheresis (blood washing) is a procedure with which blood components or disease-causing substances are removed from the blood. Read everything about apheresis, how it works and the risks it carries.

What is an apheresis?

Apheresis is a procedure that deliberately removes blood constituents or disease-causing substances from blood or blood plasma. This happens outside the body (extracorporeal) - with the help of an apheresis machine. The cleaned blood or blood plasma then flows back into the body. Aphereses are divided into:

Erythrocyt apheresis: Gaining red blood cells (erythrocytes)
Leukapheresis: Gaining white blood cells (leukocytes)
Stem cell apheresis: harvesting stem cells
Thrombocytapheresis: Gaining blood platelets (thrombocytes)
Plasmapheresis: separation of blood plasma from whole blood
Lipid apheresis or LDL apheresis: separation of cholesterol and blood lipids
Apheresis of disease-causing substances

Blood and blood components

Whole blood consists of about 45 percent solid components, about 55 percent makes up blood plasma, which serves as a transport medium for glucose (sugar), lipids (fats), proteins (protein), hormones, coagulation factors and dissolved gases. The solid components of the blood are separated from the plasma by centrifugation - they are made up of:

Erythrocytes: red blood cells that carry oxygen to the cells.
Leukocytes: White blood cells that are responsible for the immune system.
Platelets: platelets that allow blood to clot when injured.

When is an apheresis performed?

Basically, two apheresis procedures can be distinguished:

Preparative apheresis

In preparative apheresis, blood components are obtained for later use as a therapeutic agent. These include above all platelets, stem cells, erythrocytes and leukocytes. Stem cell apheresis is now replacing bone marrow removal from cancer patients in whom the blood-forming system is damaged as part of chemotherapy or steel therapy. The stem cells obtained in this way are returned to the patient after the therapy and begin to rebuild the blood. In the case of autologous donations, in contrast to allogeneic donations, the donor and recipient are the same person.

Therapeutic apheresis

Therapeutic apheresis is a cleansing process used to remove substances from the blood. In lipid apheresis, for example, the doctor cleans the blood of severe lipid metabolism disorders of LDL (low density lipoproteins) - a transporter for cholesterol or other fats. Lipid apheresis is always used when the blood lipid levels can no longer be reduced by diet or medication. In the case of kidney problems, dialysis is used as a so-called kidney replacement method and cleanses the blood of toxic substances. Leukapheresis reduces an excess of leukocytes in cancers of the blood-forming system (leukemia). If cells attack your own body as part of immune diseases, these can be removed by plasmapheresis.

What do you do with an apheresis?

Before any preparative apheresis, the doctor will explain the procedure, possible side effects and dangers to you. In addition, when clarifying the medical history (anamnesis), the doctor pays particular attention to ensure that you have no gastrointestinal diseases, allergies, convulsions, cardiovascular diseases, bleeding tendencies or infections and that you have enough blood components of your own. You must stop taking anticoagulant drugs one week before apheresis.

Before the actual apheresis, the doctor usually places cannulas (hollow needles) in two of the donor's arm veins. The donor blood flows from one of them into a closed, sterile tube system that can only be used once. There an anticoagulant (anticoagulant) is added to the blood and the mixture is passed on to a cell separator. The various blood components are separated from one another by centrifugation. In addition, individual substances are obtained through filtration. and the blood returned to the donor via the other arm vein. The anticoagulant is easily broken down by the liver.

In stem cell apheresis, the stem cells are first hormonally stimulated and flushed out of the bone marrow into the blood.

Therapeutic apheresis is carried out like preparative apheresis. Especially in LDL apheresis or lipid apheresis, the addition of anticoagulants (heparin) or certain antibodies causes the fats to bind to larger structures that can be filtered off.

What are the risks of apheresis?

Apheresis is a well tolerated procedure.
A so-called vasovagal reaction can occur during apheresis. The blood vessels expand, the heartbeat slows down and the blood pressure drops. Typical symptoms are paleness, drowsiness, nausea, and irregular breathing. The puncture site can also become infected or a bruise (hematoma) may form. In very rare cases, the breakdown of the citrate results in a short-term, acute calcium deficiency, which manifests itself as shivering, tingling in the fingertips, toes, lips or tongue. The administration of calcium relieves the symptoms and prevents very rare cardiac arrhythmias.

What do I have to consider after an apheresis?

After an apheresis, you will remain under supervision for at least half an hour. The doctor measures blood pressure and pulse rate to assess circulatory stability and takes care of the puncture site. Hospitalization is not necessary. All complaints can still occur after the apheresis has been completed and should be clarified by a doctor immediately.

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