•Development of a color meter which can quantify the concentration of biomarkers for POCT device applications.•Sensitive detection of total protein on paper based microfluidic device.•Programmable handheld device for colorimetric liver function tests. This paper reports the development and fabrication of a low-cost handheld point of care device that can quantify the concentration of biomarkers using a paper microfluidic assay. The commercially available light-to-digital converting sensor was used to achieve this objective. This RGB sensor was efficient in the digital values of the red, green, and blue components of the sample or object. It has an inbuilt white LED source, an array of photodiodes with color filters, an analog-to-digital converter module, and also an IR blocking filter. The sensor was interfaced with the Arduino UNO board, and the corresponding results were displayed on the serial monitor. This device was tested for manually prepared primary color samples and also for total protein. The colorimetric detection of protein was performed for 1 g dL-1 to 14 g dL-1 concentrations on a paper microfluidic device. The change in color intensity of the paper device with an increase in total protein concentration was monitored and calibrated the device for real sample analysis.