Patent ID: 8676288

Claim:
A device for measuring glucose in a bodily fluid, the device comprising: a sensor operably connected to an electronic circuit and configured to continuously measure a signal associated with a glucose concentration in a host, the sensor comprising a working electrode and a reference electrode, wherein the working electrode and the reference electrode are configured for implantation in a subcutaneous tissue of the host; and a membrane disposed on a portion of the sensor, configured to provide at least two phases of sensor function, wherein the at least two phases of sensor function comprise: a first phase that occurs after implantation of the device in the subcutaneous tissue and during which the signal provides an unstable measurement of the glucose concentration in the host; and a second phase that occurs after the first phase and during which the signal provides a stable measurement of the glucose concentration in the subcutaneous tissue of the host, wherein at least 95% of glucose concentration values measured by the signal are within 25% of one or reference glucose values over a period of time no less than 3 days in the subcutaneous tissue of the host, and wherein the one or more reference values are determined by analysis of the host's blood glucose; wherein the device is configured to respond substantially linearly to changes in glucose concentration at a glucose concentration of up to about 400 mg/dL.