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 to capture a desired fraction of the biological sample. A force is provided that is generally perpendicular to gravity. The force is movable between a first position adjacent the input zone multiple other positions adjacent various purification, protein analysis, separation and extraction zones. The force captures the fraction-bound solid phase substrate and the fraction-bound solid phase substrate moves from the input zone to the other zones to perform a multi-step assay on the isolated fraction within the device.