System and methods for processing analyte sensor data for sensor calibration

• US 8,611,978 B2
• Filed: 01/07/2010
• Issued: 12/17/2013
• Est. Priority Date: 03/10/2005
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Apurv Ullas, Goode, Paul V., Brauker, James H.
• Primary Examiner(s): Natnithithadha, Navin
• APPLICATION: US 20100168546A1
• Time in patent office: 1440 Days
• Field of Search: 600/309, 600345-366
• US Class Current: 600/347
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/1451 for interstitial fluid
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/14735 comprising an immobilised reagent
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• 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: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

Systems and methods for processing sensor analyte data are disclosed, including initiating calibration, updating calibration, evaluating clinical acceptability of reference and sensor analyte data, and evaluating the quality of sensor calibration. The sensor can be calibrated using a calibration set of one or more matched sensor and reference analyte data pairs. Reference data resulting from benchtop testing an analyte sensor prior to its insertion can be used to provide initial calibration of the sensor data. Reference data from a short term continuous analyte sensor implanted in a user can be used to initially calibrate or update sensor data from a long term continuous analyte sensor.

Claims

1. A method for simultaneously utilizing at least two analyte sensors, the method comprising:

receiving sensor data from a first analyte sensor for a first time period;

receiving sensor data from a second analyte sensor for a second time period, wherein the second analyte sensor is transcutaneously implanted in a host and wherein the second analyte sensor has an initial instability time period; and

processing the sensor data, using processor electronics, from the second analyte sensor using the sensor data from the first analyte sensor, wherein the first time period and the second time period overlap and wherein the overlapping time period comprises the initial instability time period of the second analyte sensor, wherein the processing comprises a) utilizing the sensor data from the second analyte sensor to assess performance of the first analyte sensor or b) calibrating sensor data from the second analyte sensor.

2. The method of claim 1, wherein the first analyte sensor and the second analyte sensor are each glucose sensors.

3. The method of claim 1, wherein the sensor data from the first analyte sensor comprises at least one sensor data point, wherein processing the sensor data from the second analyte sensor using the sensor data from the first analyte sensor comprises calibrating the sensor data from the second continuous analyte sensor by forming at least one matched data pair by matching at least one sensor data point from the first analyte sensor to at least one sensor data point from the second analyte sensor and forming a calibration set comprising at least one matched data pair.

4. The method of claim 1, wherein each of the first analyte sensor and the second analyte sensor have a predefined lifespan in the range of one hour to three weeks.

5. The method of claim 1, wherein each of the first analyte sensor and the second analyte sensor have a predefined lifespan greater than three weeks.

6. The method of claim 1, wherein the processing the sensor data from the second analye sensor using the sensor data from the first analyte sensor comprises calibrating the sensor data from the second analyte sensor by:

constructing a first curve from the sensor data from the first transcutaneous continuous analyte sensor;

constructing a second curve from the sensor data from the second transcutaneous continuous analyte sensor; and

matching the first curve with the second curve.

7. The method of claim 1, wherein the processing comprises determining, using the processor electronics, when the second analyte sensor is stable.

8. The method of claim 7, wherein the determining comprises analyzing, using the processor electronics, data from the second sensor.

9. The method of claim 1, wherein the initial instability time period is predetermined.

10. The method of claim 1, wherein the processing includes determining an end of the initial instability time period and calibrating the second sensor data using the first sensor data responsive to determining the end of the initial instability time period.

11. The method of claim 1, wherein the initial instability time period comprises a time for the second analyte sensor to equilibrate with the host'"'"'s tissue.

12. The method of claim 1, wherein the first analyte sensor has a predefined lifespan and wherein the overlapping time period is near the end of the predefined lifespan.

13. The method of claim 1, wherein the processing is performed in substantially real-time.

14. A system for calibrating a substantially continuous glucose sensor, comprising:

a first continuous glucose sensor;

a second continuous glucose sensor;

a first sensor data receiving module operably linked to said first sensor and configured to receive at least one sensor data point from said first sensor;

a second sensor data receiving module operably linked to said second sensor and configured to receive at least one sensor data point from said second sensor; and

a processor module in data communication with said first sensor data receiving module linked to said first sensor and further in data communication with said second sensor data receiving module linked to said second sensor, said processor module configured to calibrate the sensor data from the second sensor using pre-implant information associated with the second sensor and to adjust or to confirm the calibration of the sensor data from the second sensor using the sensor data from the first sensor, wherein the pre-implant information comprises predetermined sensitivity information derived from in vitro testing of a continuous glucose sensor.

15. The system of claim 14, further comprising a receiver operably connected to the first and second continuous glucose sensors, wherein the receiver comprises the first sensor data receiving module and the second sensor data receiving module.

16. The system of claim 15, wherein the receiver further comprises the processor module.

17. The system of claim 14, wherein the processor module is configured to calibrate the sensor data from the second sensor in substantially real-time.

18. A method for simultaneously utilizing at least two analyte sensors, the method comprising:

receiving sensor data from a first continuous analyte sensor for a first time period;

receiving sensor data from a second continuous analyte sensor for a second time period; and

processing the sensor data, using processor electronics, from the second continuous analyte sensor using the sensor data from the first continuous analyte sensor, wherein the processing comprises a) assessing performance of the second analyte sensor or b) calibrating sensor data from the second analyte sensor, and wherein the processing is based on at least one of calibration information, time lag information or drift information from the first continuous analyte sensor.

19. The method of claim 18, wherein the processing is based on at least one of time lag information or drift information.

20. The method of claim 18, wherein the processing comprises assessing performance of the second analyte sensor.

21. The method of claim 18, wherein the processing comprises calibrating sensor data from the second analyte sensor.

22. The method of claim 18, wherein the first second analyte sensor and the second analyte sensor each comprise a continuous glucose sensor.

23. The method of claim 18, wherein the processing is performed in substantially real-time.

24. The method of claim 18, wherein the first and second time periods overlap.

25. A system for simultaneously utilizing at least two analyte sensors, the system comprising:

a first continuous analyte sensor configured to generate sensor data for a first time period;

a second continuous analyte sensor configured to generate sensor data for a second time period; and

processing electronics configured to receive the sensor data from the first and second continuous analyte sensors during the first and second time periods, wherein the processing electronics are configured to estimate glucose values for the second time period based on sensor data from the second continuous analyte sensor for the second time period and at least one of calibration information, time lag information or drift information from the first continuous glucose sensor for the first time period.

26. The system of claim 25, wherein the sensor data from the first analyte sensor comprises at least one of time lag information or drift information.

27. The system of claim 25, wherein the processing electronics are further configured to assess performance of at least one of the first or second analyte sensors.

28. The system of claim 25, wherein the processing electronics are further configured to calibrate the second analyte sensor.

29. The system of claim 25, wherein the first second analyte sensor and the second analyte sensor each comprise a continuous glucose sensor.

30. The system of claim 25, wherein the processing electronics are configured to estimate during the first and/or second time periods.

31. A system for simultaneously utilizing at least two analyte sensors, the system comprising:

a first continuous analyte sensor configured to generate sensor data for a first time period;

a second continuous analyte sensor configured to generate sensor data for a second time period; and

processing electronics configured to process the sensor data from the second analyte sensor using the sensor data from the first analyte sensor, wherein the first time period and the second time period overlap and wherein the overlapping time period comprises the initial instability time period of the second analyte sensor.

32. The system of claim 31, wherein each of the first analyte sensor and the second analyte sensor have a predefined lifespan in the range of one hour to three weeks.

33. The system of claim 31, wherein each of the first analyte sensor and the second analyte sensor have a predefined lifespan greater than three weeks.

34. The system of claim 31, wherein the processing electronics are configured to calibrate the sensor data from the second analyte sensor by:

constructing a first curve from the sensor data from the first transcutaneous continuous analyte sensor;

constructing a second curve from the sensor data from the second transcutaneous continuous analyte sensor; and

matching the first curve with the second curve.

35. The system of claim 31, wherein the processing electronics are configured to determine when the second analyte sensor is stable.

36. The system of claim 35, wherein the processing electronics are configured to determine by analyzing the sensor data from the first analyte sensor.

37. The system of claim 31, wherein the initial instability time period is predetermined.

38. The system of claim 31, wherein the processing electronics are configured to determine an end of the initial instability time period and calibrate the second sensor data using the first sensor data responsive to determining the end of the initial instability time period.

39. The system of claim 31, wherein the initial instability time period comprises a time for the second analyte sensor to equilibrate with the host'"'"'s tissue.

40. The system of claim 31, wherein the first analyte sensor has a predefined lifespan and wherein the overlapping time period is near the end of the predefined lifespan.

41. The system of claim 31, wherein the processing electronics are configured to process the sensor data from the second analyte sensor using the sensor data from the first analyte sensor during the first and/or second time periods.

42. The system of claim 31, wherein the first analyte sensor and the second analyte sensor are each glucose sensors.

43. The method of claim 31, wherein the sensor data from the first analyte sensor comprises at least one sensor data point, wherein the sensor data from the second analyte sensor comprises at least one sensor data point, and wherein the processing electronics are configured to process the sensor data from the second analyte sensor using the sensor data from the first analyte sensor by calibrating the sensor data from the second continuous analyte sensor, wherein the calibrating comprises forming at least one matched data pair by matching at least one sensor data point from the first analyte sensor to at least one sensor data point from the second analyte sensor and forming a calibration set comprising at least one matched data pair.