The present invention relates to a method for estimating blood glucose levels using a noninvasive optical coherence tomography- (OCT-) based blood glucose monitor. An algorithm correlates OCT-based estimated blood glucose data with actual blood glucose data determined by invasive methods. OCT-based data is fit to the obtained blood glucose measurements to achieve the best correlation. Once the algorithm has generated sets of estimated blood glucose levels, it may refine the number of sets by applying one or more mathematical filters. The OCT-based blood glucose monitor is calibrated using an Intensity Difference plot or the Pearson Product Moment Correlation method.