A gravity assisted disposable system for separating a biological sample material into two or more distinct submaterials through sedimentation comprising: a sample delivery conduit; and a bag-set in fluid communication with the sample delivery conduit and wherein said bag-set is a functionally-closed fluid path comprising; a tubing assembly for transferring the biological material through the bagset; a separation assembly (7,9) in fluid communication with the tubing assembly configured to receive the biological sample from the sample delivery conduit and to allow for sedimentation of a submaterial from the biological material; and a filter assembly in fluid communication with the tubing assembly and the separation assembly, wherein said filter assembly is configured to receive the biological material and at least one submaterial from the separation assembly through the tubing assembly for filtering and to return retentate material to the separation assembly through a retentate conduit and deliver permeate material to the separation assembly through a permeate conduit; the system being characterized in that the bag set includes a supply bag configured to supply an aggregating agent to the separation assembly. a sample delivery conduit; and a bag-set in fluid communication with the sample delivery conduit and wherein said bag-set is a functionally-closed fluid path comprising; a tubing assembly for transferring the biological material through the bagset; a separation assembly (7,9) in fluid communication with the tubing assembly configured to receive the biological sample from the sample delivery conduit and to allow for sedimentation of a submaterial from the biological material; and a filter assembly in fluid communication with the tubing assembly and the separation assembly, wherein said filter assembly is configured to receive the biological material and at least one submaterial from the separation assembly through the tubing assembly for filtering and to return retentate material to the separation assembly through a retentate conduit and deliver permeate material to the separation assembly through a permeate conduit; the system being characterized in that the bag set includes a supply bag configured to supply an aggregating agent to the separation assembly. a tubing assembly for transferring the biological material through the bagset; a separation assembly (7,9) in fluid communication with the tubing assembly configured to receive the biological sample from the sample delivery conduit and to allow for sedimentation of a submaterial from the biological material; and a filter assembly in fluid communication with the tubing assembly and the separation assembly, wherein said filter assembly is configured to receive the biological material and at least one submaterial from the separation assembly through the tubing assembly for filtering and to return retentate material to the separation assembly through a retentate conduit and deliver permeate material to the separation assembly through a permeate conduit; the system being characterized in that the bag set includes a supply bag configured to supply an aggregating agent to the separation assembly.