The invention pertains to a filtration device (10), comprising a central jacket and first and second side panels interlocked together around said jacket, each of said side panels comprising a membrane (12A,12B) sealed thereto. The invention further pertains to a combination of said filtration device and a vial comprising an interior volume configured to receive said filtration device in a first orientation effective for concentrating sample in said sample chamber when subjected to a driving force, and in a second orientation effective for recovering concentrated sample when subjected to a driving force.