Blood products are medicinal products of human origin and are subject to international and national laws regarding collection, processing, storage and use.

They are pharmaceuticals manufactured from whole blood or its components. Red cell concentrates, platelet concentrates, and plasma are manufactured for direct transfusion. 

Industrial plasma, cryopreparations or factor concentrates must be processed appropriately beforehand - this is usually done by pharmaceutical companies.

When blood is donated, 450ml is taken from the donor to make the blood unit and a further 50ml to carry out the tests.

Whole blood is currently only used as a starting product in Europe. However, studies are underway on the emergency treatment of trauma patients in war conditions.

The whole blood bag is centrifuged, the plasma collected at the top is removed, and pure red cells - erythrocytes - remain.

These are suspended in a salt nutrient solution (SAG-M), so they have a volume of about 300ml and a haematocrit of 50-70%. The haemoglobin content of an erythrocyte concentrate is, on average, 40mg Hb/dl. Finally, these cells are passed through a leucocyte filter, which removes divisible leucocytes from the product. The final product must have no more than 10^6 leucocytes/bag.

Platelets are small nucleated cells whose function is to stop bleeding. During centrifugation, they are found between the plasma and the erythrocytes - the so-called buffy coat. 

Plasma is the liquid part of blood. After a whole blood unit has been centrifuged, the erythrocytes are at the bottom, and the plasma is at the top. Between the two phases are the white cells, and the plasma just above the interface is very rich in platelets.

The plasma obtained from a donation (approx. 250ml) can be used as a single donation for transfusion. Or it is sold frozen to the pharmaceutical industry, where several hundred plasma units are pooled together. In this way, the individual differences in the plasma factors of the individual donors are balanced out. From this pool, either plasma or various drugs can be produced.

Last update on 12.08.2023.