Sample preparation unit and sample preparation device

A sample preparation unit, preferably for sterility testing, comprising a housing body (2) including at least two ports (4, 5, 6) adapted to serve as fluid inlet and/or fluid outlet, a membrane support (10), and a lid part (3) provided such that a membrane chamber (12) is defined adjacent said membrane support (10). One of said at least two ports (4,5,6) is arranged so as to allow a fluid transfer to/from a first volume of said membrane chamber (12, 12a, 12b)) at a position upstream of a membrane (8) to be placed on said membrane support (10), and the other of said ports (4, 5, 6) is arranged to allow fluid transfer to/from a second volume of said membrane chamber (12, 12a, 12b) at a position downstream of a membrane (8) to be placed on said membrane support (10). A movable part (7) is provided on said housing body (2) such that said movable part (7) and said housing body (2) are movable relative to each other, preferably by rotation, thereby selectively interrupting/establishing the fluid transfer between at