Patent ID: 8747670

Claim:
A centrifugal filtration assembly, comprising: a filtration device and at least one filtration device holder; said filtration device comprising a sample reservoir, a pair of spaced membranes each supported by an underdrain support comprising a series of channels, grooves or surface textures to capture filtrate, a plurality of drain holes for draining said filtrate, and a retentate chamber, said filtration device having an external diameter; said device holder comprising a housing having an open end and a first internal diameter larger than said external diameter of said filtration device, said device holder having a shoulder within said housing spaced from said open end and defining a second internal diameter smaller than said external diameter of said filtration device; wherein said filtration device is insertable into said device holder in a spin mode whereby filtrate from said filtration device flows from said drain holes into said device holder housing, and in a reverse spin mode whereby retentate in said retentate chamber flows into said device holder housing, and wherein the extent of the insertion of said filtration device into said device holder in either said spin mode or said reverse spin mode is limited by said shoulder.