Patent ID: 8628729

Claim:
A three-dimensional device for assay of a fluid sample, the device comprising at least first and second stacked, porous, hydrophilic layers each of which comprise a pattern of fluid-impermeable barriers that substantially permeate the thickness of the layer to define boundaries within each said layer of one or more porous hydrophilic regions of said hydrophilic layers that wick fluids laterally by capillary action through the porous hydrophilic regions of said hydrophilic layers; a fluid-impermeable layer disposed between said first and second layers defining one or more openings communicating vertically between hydrophilic regions in separate layers, said opening being in fluidic contact with at least one of said porous hydrophilic regions within each of said first and second layers; a porous hydrophilic medium disposed in a said opening in fluidic contact with at least one of said hydrophilic regions within each of said first and second layers; and one or more reagents disposed in fluid communication with a said hydrophilic region and with a detection zone in a hydrophilic region for colorimetrically detecting the presence of an analyte in a said detection zone.