[Adverse effects due to unstable blood products]

Most discussions of blood transfusion cover risks and side effects, while the daily benefits of donor systems and transfusion concepts for modern medicine are taken for granted. Even though in this report side effects are a major part of the content, we should be aware that today's component concept leads to a remarkable quality level of blood products. After a historical introduction we present a patient with transfusion transmitted anti-hepatitis A IgM antibodies and a delayed type hemolytic transfusion reaction induced by a boostered anti-Fyb alloantibody. This case demonstrates that the safety of transfusions depends on both the blood product and the patient's transfusion history. In the second part we summarize side effects from transfused blood products: (1) transmission of infectious diseases and the risk of blood products testing falsely negative, (2) immune mediated side effects, (3) immuno-modulations by blood transfusions, (4) side effects caused by human error. Minimizing transfusion risks is not only the task of the doctors specialized in transfusion medicine, but can only be achieved by close cooperation between all the persons associated with each step, from motivating unpaid blood donors, evaluation of donors, phlebotomy, viral testing, preparation of components, storage, and transportation conditions, to adequate indications and transfusions for the patients.