[Evaluation of risks related to blood transfusions in industrialized countries].

Although numerous progresses have been accomplished, transfusion of labile blood products still has side effects. Transfusion-associated risks are related to the complex environment of the transfusion chain which goes from volunteers for blood collection to receivers of products. Severe hemolytic accidents remain very worrying and neglected problems. Risks related to products are mostly infectious; hepatitis C has become the major infectious risk, even if contaminations linked to the serological window of HIV are still worrying. Measurement of residual risks can be done a priori, by modeling existing data, or a posteriori, by epidemiological studies. The issue of new risks, related to the diffusion of new products, or to unconventional infectious agents, underscores the importance of setting up a blood transfusion surveillance mechanism.