A device and a method are provided for isolating a fraction in a biological sample. The fraction is bound to solid phase substrate to define a fraction-bound solid phase substrate. The device includes an input zone for receiving the biological sample therein and a second zone for receiving an isolation fluid therein. A force is provided that is generally perpendicular to gravity. The force is movable between a first position adjacent the input zone and a second position adjacent the isolation zone. The force captures the fraction-bound solid phase substrate and the fraction-bound solid phase substrate moves from the input zone to the isolation zone in response to the force moving from the first position to the second position.