A method for determining a pressure of a medical fluid in a fluid line with the use of at least one centrifugal pump (11),characterized by the step:Determining the pressure upstream of the centrifugal pump (11), taking into account an indication of a pressure downstream of the centrifugal pump (11) or determining the pressure downstream of the centrifugal pump (11), taking into account an indication of a pressure upstream of the centrifugal pump (11), in each caseunder be taken into account at least an indication of the volume flow in the fluid line or at least an indication of a rotational speed of the centrifugal pump (11),the centrifugal pump (11) or sections of the centrifugal pump (11) for the determination of the pressure upstream of the centrifugal pump (11) as a portion of a disposable cassette is designed.
