The present invention relates to an apparatus (10) for perfusing an organ or tissue (20) comprising a perfusion circuit for perfusing the organ or tissue； a controller (400) configured to control the apparatus； and a detector configured to: detect an optional component of the apparatus (10), such as optional flow control clamps (127, 137), and provide a signal to the controller (400) indicative of the presence of the optional component, wherein the controller (400) is configured to control the perfusion circuit in a first mode when the optional component is detected and to control the perfusion circuit in a second mode when the optional component is not detected.The first mode may be a flow control mode and the second mode may be a pressure control mode.
