Systems and methods for testing visible chemical reactions of a reagent are provided. In one implementation, the method may include receiving from an image sensor associated with a mobile communications device an image of a reagent with a plurality of colored test reagent pads in proximity to a colorized surface having a plurality of colored reference elements of differing shades. The method further includes using the differing shades of the plurality of colored reference elements to determine local illumination conditions. Thereafter, the method includes using the determined local illumination conditions and an analysis of a depiction of the plurality of colored test reagent pads in the image to determine an extent of a chemical reaction on the reagent. Then the method includes causing the mobile communications device to provide to the user an indication that the testing of the reagent is complete.