An apparatus is adapted to centrifuge and furthermore automatically handle a container (10) for separating a component, such as fibrin monomer, from plasma. The container (10) comprises a cylindrical member (11) and a piston (25) displaceable therein and comprising a tubular piston rod (12), which extends through the top wall. The piston (25) divides the cylindrical member (11) into a first chamber positioned above said piston (25) between said piston and said top wall and a second chamber positioned below said piston (25). The apparatus comprises a supporting turntable (1) with means for releasably retaining the cylindrical member (11), said supporting turntable being connected to a first activating mechanism (5) for rotating the supporting turntable (1) with the container (10) about the central axis thereof. The apparatus comprises furthermore a rotatably journalled piston activating mechanism (13, 15, 16) adapted to activate the piston by means of a second activating means (21). A heat-emitting device (26, 27) is provided opposite the position of the cylindrical member (11) in the apparatus.