Abstract: An apparatus includes an analyte sensor, a memory, and a processor. The processor monitors, using the analyte sensor, an analyte of a patient during a time period to obtain measured analyte data for the analyte and monitors other measured sensor data indicative of a physiological state of the patient during the time period. The processor also determines, based on the physiological state of the patient during the time period, expected analyte data for the analyte and determines a correction factor based on the expected analyte data and the measured analyte data. The correction factor is indicative of an error in calibration of the analyte sensor. The processor also determines whether recalibration of the analyte sensor is possible. If recalibration is possible, the processor recalibrates the analyte sensor based on the correction factor, and if recalibration is not possible, the processor recommends, to the patient, to replace the analyte sensor.