Patent ID: 7711402

Claim:
A device for measuring glucose in a bodily fluid, the device comprising: a sensing mechanism operably connected to an electronic circuit and configured to continuously measure a signal associated with a glucose concentration in a host for a period of time greater than 3 days, the sensing mechanism comprising a working electrode, a counter electrode, and a reference electrode, wherein the working electrode, the counter electrode, and the reference electrode are exposed on a single continuous substrate surface, and wherein the working electrode, the counter 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 sensing mechanism, wherein the device is configured to provide at least two phases of sensor function, wherein the at least two phases comprise: a first phase that occurs after implantation of the device and during which the signal provides a substantially 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 substantially stable measurement of the glucose concentration in the host, wherein at least 95% of glucose concentration values measured by the signal are within 25% of one or more reference values over a useful life of the device, and wherein the one or more reference values are determined by analysis of blood, wherein the device is configured to respond substantially linearly to changes in glucose concentration at a glucose concentration of up to about 500 mg/dL or more.