There is a vital need for portable and cost-effective point-of-care (PoC) testing technologies that provide reliable and rapid results. Lateral Flow Immunoassays (LFIA) are suitable PoC diagnostic tools with the potential for use in a wide variety of field applications ranging from uses in clinical diagnostics to aiding law enforcement. Quick and reliable diagnosis of non-communicable diseases (NCD) like diabetes is vital especially in developing countries like India where the burden of these diseases is very high and is increasing day by day. In this paper, we have presented the design of smartphone-based fully quantitative LFIA analyser, An automatic image processing algorithm is also described. A repeatability study was done with stable fluorescence reference cartridges. The Coefficient of Variation (CoV) for repeatability study was calculated and it was found to be good (< 1.5%). The instrument was tested with blood samples to generate a calibration curve for Glycated Haemoglobin (HbA1c) with respect to standard lab instrument. Three different set of settings parameters were used in smartphone camera their calibration curve formed. All three curves were linearly correlated with R2-value greater than 0.985. Finally, the calibration curve was validated through three HbA1c blood sample tests- for each sample, CoV was less than 5%. The PhoneQuant analyser is the portable cost-effective solution to traditional bulky LFIA analysers and it has good potential to be deployed at physician's desk or for in-home PoC testing for quick and reliable diagnosis. © 2017 IEEE.