1. A noninvasive method of determining estimated blood glucose levels in a biological tissue of a subject using an optical coherence tomography-based blood glucose monitor comprising a sensor and at least one algorithm, the method comprising the steps: (a) selecting a wavelength of light for which μ s , an absorption coefficient of the biological tissue, is small relative to μ s , a scattering efficient of the tissue for the selected wavelength of light; (b) continuously scanning a two-dimensional surface area of the biological tissue and interferometrically scanning the two-dimensional surface area of the biological tissue in a depth dimension with the light during a time period; (c) averaging the data obtained by interferometrically scanning the two-dimensional surface area of the biological tissue in a depth dimension with the light to generate a multitude of optical coherence tomography scan data lines in the time period, wherein the x-axis of each optical coherence tomography scan data line is depth and the y-axis of each optical coherence tomography scan data lines is intensity; (d) calibrating the optical coherence tomography-based sensor against at least two invasively obtained blood glucose measurements taken during the time period; and (e) allowing the calibrated optical coherence tomography-based sensor and the at least one algorithm to determine an estimated blood glucose level in the biological tissue.