A blood bag system includes a BC pooling bag for centrifugation of a buffy coat, a filter for removing white blood cells from a supernatant liquid transferred from the BC pooling bag, a platelet preserving bag for reserving the supernatant liquid that has passed through the filter, a first tube connecting the BC pooling bag and an inlet of the filter, a second tube connecting the platelet preserving bag and an outlet of the filter, and a cassette to be fixed in the centrifugation and separation apparatus. The first tube and the second tube are disposed within the cassette. The cassette includes a first clamp section for closing and opening the first tube, and a second clamp section for closing and opening the second tube.

Plasma/cell concentrator apparatus and methods are described herein for concentrating constituents from a fluid. Generally, a volume of the fluid may be urged from a first reservoir to a second reservoir through a fluid channel and a volume of desiccant for mixing with the fluid may be introduced to create a mixture. This fluid and desiccant mixture may be passed between the first and second reservoirs until one or more components from the fluid are absorbed by the desiccant. After mixing, the fluid may be withdrawn through a withdrawal channel which is in fluid communication with the fluid channel while preventing the desiccant from passing into the withdrawal channel.

The invention provides a filtering and centrifugation device, comprising a barrel, a volume in the barrel for receiving a fluid sample to be processed, a filter medium, at least one piston movable in the barrel to force fluid in the volume through the filter medium to produce a filtrate, and a space for pelleting particulate material. The device is centrifugeable, and said space is located in or communicates with the volume and is located preferably away from the filter medium such that the particulate material does not or at least not completely clog the filter medium during such centrifugation of the device. The invention also provides a method for the sterile filtration of a sample, comprising the steps of introducing the sample into the volume of such a device, subjecting the device to centrifugation to pellet particulate material contained in the sample at the space away from the filter medium, and applying force to the piston(s) to force fluid of the sample in the volume through the filter medium to produce a filtrate. By providing the space for pelleting the particulate material under the influence of the centrifugation force, the clogging of the filter medium can be avoided or considerably delayed. Further, the entire process can be performed in the same device without having to remove the sample for any intermediate clarification steps.