DEVICE AND METHOD FOR DETERMINING ANALYTE LEVELS

• US 20100204555A1
• Filed: 04/19/2010
• Published: 08/12/2010
• Est. Priority Date: 03/04/1997
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Shults, Mark C., Updike, Stuart J., Rhodes, Rathbun K.
• Granted Patent: US 7,974,672 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: C12Q 1/006 for glucose

Abstract

Devices and methods for determining analyte levels are described. The devices and methods allow for the implantation of analyte-monitoring devices, such as glucose monitoring devices, that result in the delivery of a dependable flow of blood to deliver sample to the implanted device. The devices comprise a unique microarchitectural arrangement in the sensor region that allows accurate data to be obtained over long periods of time.

Claims

1. A system for processing sensor data from a continuous analyte sensor, comprising:

a sensing mechanism comprising an electrode configured for implantation in a subcutaneous tissue of a host, wherein the sensing mechanism is configured to continuously measure an analyte concentration, whereby sensor data associated with the subcutaneous analyte concentration is generated; and

electronic circuitry operably connected to the sensing mechanism and configured to provide an initial in vivo calibration of the sensor data for an initial calibration time period using only pre-implant calibration information, wherein the electronic circuitry is further configured to perform periodic recalibration after the initial calibration time period, and wherein the system is configured to provide a substantially accurate measurement of the analyte concentration in the host such that at least 95% of calibrated sensor analyte values are within 25% of actual analyte values during and after the initial calibration time period.

2. The system of claim 1, wherein the pre-implant calibration information comprises a single point value obtained from an in vitro calibration.

3. The system of claim 2, wherein the in vitro calibration is obtained by measuring at least two different analyte concentrations.

4. The system of claim 2, wherein the in vitro calibration is obtained at about 37 degrees C.

5. The system of claim 1, wherein the periodic recalibration is based on a reference analyte value.

6. The system of claim 5, wherein the reference analyte value is correlated with a time-shifted sensor data value.

7. The system of claim 1, wherein the recalibration comprises an adjustment in sensor gain.

8. The system of claim 1, wherein the initial calibration time period is greater than about 3 days.

9. The system of claim 1, wherein the initial calibration time period is greater than about 5 days.

10. The system of claim 1, wherein the initial calibration time period is greater than about 7 days.

11. The system of claim 1, wherein the initial calibration time period is about one month.

12. The system of claim 1, wherein the analyte is glucose, and wherein the sensing mechanism is configured to respond substantially linearly to changes in glucose concentration at glucose concentrations ranging from about 40 mg/dL to about 500 mg/dL.

13. The system of claim 1, wherein the system is configured to provide a stable sensor offset during a period of time of continuous measurement of an analyte concentration in the host.

14. The system of claim 1, wherein the electronic circuitry is configured to determine trends in analyte concentration.

15. The system of claim 1, wherein the electronic circuitry is configured to physically couple the sensing mechanism.

16. The system of claim 1, wherein the electronic circuitry is configured to couple, via radio telemetry, to the sensing mechanism.

17. The system of claim 1, wherein the analyte is glucose.

18. A method for processing sensor data from a continuous analyte sensor, comprising:

receiving sensor data from an analyte sensor, the sensor data indicative of an analyte concentration in a host;

calibrating the sensor data for an initial calibration time period using only pre-implant calibration information;

periodically recalibrating the sensor data after the initial calibration time period; and

generating a substantially accurate measurement of the analyte concentration, such that at least 95% of calibrated sensor analyte values are within 25% of actual analyte values during and after the initial calibration time period.

19. The method of claim 18, wherein the pre-implant calibration information comprises a single point value obtained from an in vitro calibration.

20. The method of claim 19, wherein the in vitro calibration is obtained by measuring at least two different analyte concentrations.

21. The method of claim 19, wherein the in vitro calibration is obtained at about 37 degrees C.

22. The method of claim 18, wherein the periodically recalibrating is based on a reference analyte value.

23. The method of claim 22, wherein the reference analyte value is correlated with a time-shifted sensor data value.

24. The method of claim 18, wherein the periodically recalibrating comprises adjusting a sensor gain.

25. The method of claim 18, wherein the initial calibration time period is greater than about 3 days.

26. The method of claim 18, wherein the initial calibration time period is greater than about 5 days.

27. The method of claim 18, wherein the initial calibration time period is greater than about 7 days.

28. The method of claim 18, wherein the initial calibration time period is about one month.

29. The method of claim 18, wherein the analyte is glucose, and wherein the sensing mechanism is configured to respond substantially linearly to changes in glucose concentration at glucose concentrations ranging from about 40 mg/dL to about 500 mg/dL.

30. The method of claim 18, further comprising maintaining a stable sensor offset during a period of time of continuous measurement of an analyte concentration in the host.

31. The method of claim 18, further comprising determining trends in analyte concentration.

32. The method of claim 18, wherein the analyte is glucose.