Patent ID: 8114269

Claim:
A method of determining hydration of a sensor having a plurality of electrodes placed percutaneously or subcutaneously at a selected site in the body of a user, the method comprising the steps of: coupling a sensor electronics device to the sensor; measuring successive open circuit potential values between at least two of the plurality of electrodes; calculating the rate of change of the measured open circuit potential values as the change over time between an open circuit potential value measured earlier in time and an open circuit potential value measured later in time; comparing the open circuit potential values and the calculated rate of change to respective predetermined thresholds; determining that the sensor is hydrated if said predetermined thresholds are met; repeating, over a specified period of time, said measuring, calculating, and comparing steps if said predetermined thresholds are not met; and if said predetermined thresholds are not met after the specified period of time has been exceeded, determining that the sensor will not hydrate and notifying the user to replace the sensor.