Abstract: Fresenius AS.TEC204 is a third‐generation blood cell separatorthat incorporates the continuous centrifugal separation method andautomatic control of the cell separation process. Continuous centrifugationseparates cell components according to their specific gravity, anddifferent cell components are either harvested or eliminated asneeded. The interface between the red blood cell and plasma is opticallydetected, and the Interface Control (IFC) cooperates with differentpumps, monitors and detectors to harvest required components automatically. Thesystem is composed of three major sections; the Front Panel Unit;the Pump Unit, and the Centrifuge Unit. This unit can be used fora wide variety of clinical applications including collection ofplatelets, peripheral blood stem cells, bone marrow stem cells,granulocytes, mononuclear cells, and exchange of plasma or red cells,and for plasma treatment.