An apparatus is adapted to centrifuge a container for separating a component, such as fibrin monomer, from blood or plasma. The container includes a cylindrical member, and a piston displaceable therein and a tubular piston rod, which extends through a top wall of the cylindrical member. The piston divides the cylindrical member into a first chamber positioned above the piston between the piston and the top wall, and a second chamber positioned below the piston. The apparatus includes a supporting turntable which releasably retains the cylindrical member. The supporting turntable is connected to a first activator for rotating the supporting turntable with the container about the central axis thereof. The apparatus also includes a rotatably journalled piston activating mechanism adapted to activate the piston by a second activator. A heat-emitting device is provided opposite the cylindrical member, and an filter is provided between the heat-emitting device and the cylindrical member to block radiation emitted by the heat-emitting device that degrades protein in the blood or plasma.