Abstract: The present disclosure relates to paper microfluidic devices for use in combination with a viewing box assembly for imaging and rapid identification and quantification of target analytes in a fluid sample that is deposited onto the device such that one or more target analytes in the sample react with one or more diagnostic components on the paper, causing a detectable reaction. The reacted microfluidic device may then be placed inside an opaque viewing box having an internal light source and top panel viewing aperture through which the microfluidic device may be imaged using a mobile electronic device and graphical user-interface for purposes of detecting and quantifying the one or more target analytes. In some embodiments, the microfluidic device includes diagnostic paper and abase. In some embodiments, the microfluidic device includes a filter layer on top of diagnostic paper layer.