World Blood Donor Day – Many Important Medicines Are Derived from Blood Donations

World Blood Donor Day

Blood Components for Transfusion

Blood components derived from human blood are prepared to be suitable for transfusion. Whereas whole blood was also used for transfusions in the past, today blood donations are always separated into blood components, which can then be directly transfused as required. Concentrates of red blood cells (erythrocytes), platelets, and therapeutic plasma are transfused. The targeted and economical use of these concentrates allows for efficient treatment and supports the patient blood management approach, which aims to provide an optimal supply of blood components.

Erythrocyte concentrates are used under circumstances such as severe blood loss during surgery (acute anaemia) or treatment of chronic anaemia. Erythrocytes contain haemoglobin, which is responsible for the exchange and transport of oxygen in the lungs, cells, and tissues. Attention must be paid to blood group tolerance when administering erythrocyte concentrates. Unless there is a life-threatening emergency, a serological tolerance test must be carried out before use.

Platelets ensure that the walls of the blood vessels are sealed in the event of an injury and thus contribute to the stoppage of bleeding. Platelet concentrates are used for the treatment of thrombocytopenia (lack of platelets) or severe blood loss.

Blood plasma is the liquid and cell-free part of human blood. It can be used as therapeutic plasma if, for example, plasma volume has to be replenished in the case of very heavy bleeding.

Plasma-Derived Blood Products

Blood plasma can also be used as "source plasma". Blood plasma contains numerous proteins that can be obtained from plasma by fractionation and processed into medicinal products:

• Immunoglobulin preparations are used to treat immunodeficiency diseases. They usually contain a mixture of several immunoglobulin G (IgG) antibodies with different specificities (polyclonal antibodies). IgG is a subclass of antibodies that makes up the majority of antibodies circulating in the blood. There are also various specific immunoglobulins, such as antibodies to the rabies virus (post-exposure prophylaxis) or anti-hepatitis B virus IgG, which is used to prevent hepatitis B in newborns whose mothers have been infected with the hepatitis B virus or in people who do not form antibodies after vaccination.
• Coagulation factors are the protein components of the blood that help clot blood. Their uses include administration to patients with haemophilia in order to replace the coagulation factor that they are missing due to the disease.
• Albumins serve as transport proteins in the blood and are also responsible for the colloid osmotic pressure of the blood plasma. They can be used to stabilise blood circulation volume in the case of heavy bleeding or burns.
• Coagulation inhibitors (also called anticoagulants) are proteins that counteract blood clotting. Their uses include treatment of thrombosis (thrombophilia).
• Fibrin glue (also tissue adhesive) is a physiological two-component glue whose components fibrinogen and thrombin are obtained from blood plasma. It can be used to glue wound edges supportively to the surgical suture.

Safety of Blood and Blood Products

The Paul-Ehrlich-Institut is responsible for the safety of blood and blood products in Germany. The Institute carries out an extensive list of activities tied to the authorisation and safety monitoring of blood products. The tasks also include the identification of possible risks to blood donation system in the event of the occurrence of new infectious agents and the introduction of mandatory risk minimisation measures. The Paul-Ehrlich-Institut's regular haemovigilance reports provide transparency with regard to reports and measures related to blood products and their use in Germany. It documents all reports of serious transfusion reactions in one year and compares them with the reports from previous years. These reports shed light on the contribution of risk-minimising factors to increased safety of blood components. Information on the extraction, production, import, export, and consumption of blood and blood products can be found in the haemovigilance reports created in accordance with Section 21 of the German Transfusion Act.