1. A method for calibrating an optical coherence tomography (OCT) sensor by correlating OCT measurements with blood analyte measurements, comprising: receiving blood analyte measurements from a subject over a period of time; obtaining OCT measurements from biological tissue of the subject using an OCT sensor such that at least one OCT measurement is associated with each blood analyte measurement, each of the OCT measurements capable of being represented as a plot of intensity against depth of the biological tissue; selecting at least one portion of each of the OCT measurements that includes a selected depth, the selected portion of the OCT measurements correlating with the associated blood analyte measurements; and determining, using a processor, a calibration relationship for the OCT sensor using the selected portions of the OCT measurements and the associated blood analyte measurements.