A device (100, 300, 400, 600, 1500, 2400) to conduct an assay of an analyte in a biological sample and provide quantitative information relating to the biological sample, the device comprising: a flexible substrate (104, 304, 404, 604), wherein the flexible substrate comprises at least one paper-based portion, at least one elastomeric portion, or at least one plastic portion; a container (106, 306a, 306b) at least partially formed in or disposed on the flexible substrate to retain the biological sample; a reagent disposed in the container to generate a color change representing a degree to which the reagent reacts with the biological sample, when the biological sample is present; a plurality of reference wells (309a, 309b, 1420, 1422, 1520) within the flexible substrate, the plurality of reference wells having respective different reference color values; electronic circuitry integrated with the flexible substrate to generate at least one analysis result, the electronic circuitry comprising: at least one light source to illuminate the reagent and the biological sample, when present, to measure the color change and provide an output optical signal representing the color change; at least one photodetector to detect the output optical signal and generate an output electrical signal representing a value indicative of the color change; and at least one comparator to compare the value with the plurality of reference color values so as to generate the at least one analysis result, and at least one indicator (110, 1310, 1410, 1510, 1610, 1710) coupled to the flexible substrate, and electrically coupled to the electronic circuitry, to provide an indication of the quantitative information relating to the biological sample based at least in part on the at least one analysis result. a flexible substrate (104, 304, 404, 604), wherein the flexible substrate comprises at least one paper-based portion, at least one elastomeric portion, or at least one plastic portion; a container (106, 306a, 306b) at least partially formed in or disposed on the flexible substrate to retain the biological sample; a reagent disposed in the container to generate a color change representing a degree to which the reagent reacts with the biological sample, when the biological sample is present; a plurality of reference wells (309a, 309b, 1420, 1422, 1520) within the flexible substrate, the plurality of reference wells having respective different reference color values; electronic circuitry integrated with the flexible substrate to generate at least one analysis result, the electronic circuitry comprising: at least one light source to illuminate the reagent and the biological sample, when present, to measure the color change and provide an output optical signal representing the color change; at least one photodetector to detect the output optical signal and generate an output electrical signal representing a value indicative of the color change; and at least one comparator to compare the value with the plurality of reference color values so as to generate the at least one analysis result, and at least one light source to illuminate the reagent and the biological sample, when present, to measure the color change and provide an output optical signal representing the color change; at least one photodetector to detect the output optical signal and generate an output electrical signal representing a value indicative of the color change; and at least one comparator to compare the value with the plurality of reference color values so as to generate the at least one analysis result, and at least one indicator (110, 1310, 1410, 1510, 1610, 1710) coupled to the flexible substrate, and electrically coupled to the electronic circuitry, to provide an indication of the quantitative information relating to the biological sample based at least in part on the at least one analysis result.