Current risks in blood transfusion in Japan.

Over the past decades, the incidence of transfusion-transmitted diseases has been dramatically reduced. These reductions have been due to a multifocal approach to the collection, processing, and release of blood components. The estimated risks of transfusion-transmitted hepatitis viruses are now extremely small, but the possibility of infections with emerging pathogens always exists because preventive measures may not be available for all cases. Thus, some patients may be harmed before preventive measures are introduced. Beside transfusion-transmitted infections (TTI), unsolved residual risks such as transfusion-related acute lung injury or incompatible blood components transfusion still exist as major concerns. Continuous efforts toward research on and the prevention of adverse reaction-related blood components must be made to ensure blood safety. The purpose of this article is to introduce the concept of the current risks of transfusion including TTI, review the preventive measures already implemented, and discuss future visions for transfusion safety in Japan.