System and methods for processing analyte sensor data

• US 8,290,562 B2
• Filed: 05/03/2010
• Issued: 10/16/2012
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Goode, Paul V. Jr., Brauker, James H., Kamath, Apurv U., Carr-Brendel, Victoria
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): D'ANGELO, MICHAEL J
• Application Number:
  US12/772,842
• Publication Number:
  US 20100214104A1
• Time in Patent Office: 897 Days
• Field of Search: 600/309, 600/316, 600345-347, 600/365, 435/4, 435/14, 436/68, 422/50, 422420-429, 20440301-40315, 702/23, 604 64- 66
• US Class Current: 600/347
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• 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

Abstract

Systems and methods for processing sensor analyte data, including initiating calibration, updating calibration, evaluating clinical acceptability of reference and sensor analyte data, and evaluating the quality of sensor calibration. During initial calibration, the analyte sensor data is evaluated over a period of time to determine stability of the sensor. The sensor may be calibrated using a calibration set of one or more matched sensor and reference analyte data pairs. The calibration may be updated after evaluating the calibration set for best calibration based on inclusion criteria with newly received reference analyte data. Fail-safe mechanisms are provided based on clinical acceptability of reference and analyte data and quality of sensor calibration. Algorithms provide for optimized prospective and retrospective analysis of estimated blood analyte data from an analyte sensor.

Claims

1. A computer system for processing sensor data from a continuous glucose sensor, the computer system comprising:

a sensor data receiving module configured to receive sensor data from the continuous glucose sensor via a receiver, wherein the sensor data comprises one or more sensor data points;

a reference data receiving module configured to receive reference data from a reference glucose monitor, wherein the reference data comprises one or more reference data points;

a data matching module configured to form one or more matched data pairs by matching at least one reference data point to at least one substantially time corresponding sensor data point; and

a stability determination module configured to determine a stability of the continuous glucose sensor, at least in part by evaluating a level of oxygen.

2. The computer system of claim 1, further comprising an interface control module configured to provide output based at least in part on the stability of the sensor.

3. The computer system of claim 2, wherein the output from the interface control module comprises at least one of a numeric estimated glucose value, an indication of directional trend of glucose concentration, a graphical representation of an estimated glucose value, or combinations thereof.

4. The computer system of claim 1, wherein the reference data receiving module is configured to receive sensor data from a blood glucose test.

5. The computer system of claim 1, wherein the reference data receiving module is configured to receive reference data from an internal reference glucose monitor that is housed integrally with the computer system.

6. The computer system of claim 1, wherein the stability determination module is configured to evaluate at least one of an amplitude or a variability of a sensitivity associated with the continuous glucose sensor.

7. The computer system of claim 1, further comprising an interface control module comprising alerts configured to warn a user of a present and/or upcoming hypoglycemic and/or hyperglycemic event.

8. The computer system of claim 1, further comprising a processor module configured to predict one or more glucose values at one or more future points in time.

9. The computer system of claim 1, further comprising an interface control module configured to send the sensor data to an insulin pump.

10. The computer system of claim 9, wherein the interface control module is configured to send the sensor data to the insulin pump only when the stability determination module determines a predetermined level of stability of the continuous glucose sensor.

11. A method for processing sensor data from a continuous glucose sensor, the method comprising:

receiving sensor data from a continuous glucose sensor, wherein the sensor data comprises one or more sensor data points;

forming one or more matched data pairs by matching reference data to substantially time corresponding sensor data;

determining using processing circuitry a predetermined level of stability of the continuous glucose sensor at least in part by evaluating a level of oxygen; and

providing output reflective of the sensor data after the predetermined level of stability has been determined.

12. The method of claim 11, wherein determining a stability of the continuous glucose sensor further comprises waiting a predetermined time period of from about one minute to about six weeks after implantation of the continuous glucose sensor in a host before determining a stability associated with the continuous glucose sensor.

13. The method of claim 11, wherein providing output comprises providing at least one of an audible output, visual output, a tactile output, or combinations thereof.

14. The method of claim 13, wherein providing output further comprises indicating at least one of a numeric estimated glucose value, a directional trend of glucose concentration, a graphical representation of an estimated glucose value, or combinations thereof.

15. The method of claim 11, further comprising receiving reference data from a reference glucose monitor.

16. The method of claim 15, wherein receiving reference data from a reference glucose monitor comprises receiving a wired internal communication.

17. The method of claim 11, wherein determining a stability of the continuous glucose sensor further comprises evaluating at least one of an amplitude or a variability of a sensitivity of the continuous glucose sensor.

18. The method of claim 11, wherein providing output comprises alerting a user of a present and/or upcoming hypoglycemic and/or hyperglycemic event.

19. The method of claim 11, further comprising predicting one or more glucose values at one or more future points in time.

20. The method of claim 11, wherein providing output comprises sending the sensor data to an insulin pump.

21. The method of claim 20, wherein providing output comprises sending the sensor data to the insulin pump only when the predetermined level of stability of the continuous glucose sensor has been determined.

22. A system for processing sensor data from a continuous glucose sensor, comprising:

a sensor data module operably linked to a continuous glucose sensor and configured to receive sensor data from the continuous glucose sensor; and

a processor module associated with the sensor data module and programmed to match one or more reference data points with one or more substantially time corresponding sensor data points to form a calibration set comprising at least one matched data pair, wherein the processor module is programmed to evaluate a stability of the continuous glucose sensor at least in part by evaluating a level of oxygen, and wherein the processor module is further programmed to output information reflective of the sensor data after a predetermined level of stability has been determined.

23. The system of claim 22, wherein the predetermined level of stability is based at least in part on a time period after the continuous glucose sensor was implanted.

24. The system of claim 22, further comprising an output module associated with the processor module, wherein the output module is programmed to control output of sensor data.

25. The system of claim 24, wherein the output of sensor data indicates at least one of a numeric estimated glucose value, a directional trend of glucose concentration, a graphical representation of an estimated glucose value, or combinations thereof.

26. The system of claim 22, further comprising a reference input module configured to receive reference data from a blood glucose test, wherein the reference data comprises one or more reference data points.

27. The system of claim 22, further comprising a reference glucose monitor integral with the system and wherein the system further comprises a reference input module configured to receive an internal communication from the reference glucose monitor, wherein the internal communication comprises one or more reference data points.

28. The system of claim 22, wherein the processor module is programmed to evaluate at least one of an amplitude or a variability of a sensitivity of the continuous glucose sensor.

29. The system of claim 22, further comprising an output module comprising alerts configured to warn a user of a present and/or upcoming hypoglycemic and/or hyperglycemic event.

30. The system of claim 22, wherein the processor module is configured to predict one or more glucose values at one or more future points in time.

31. The system of claim 22, further comprising an output module configured to send the sensor data to an insulin pump.

32. The system of claim 31, wherein the output module is configured to send the sensor data to the insulin pump only when the predetermined level of stability of the continuous glucose sensor has been determined.

33. A continuous glucose sensor system, comprising:

a continuous glucose sensor configured to continuously measure a concentration of glucose in a host; and

a computer system configured to receive sensor data associated with the concentration of glucose in the host and configured to process the sensor data to provide displayable sensor data, wherein the computer system is configured to output the sensor data after a predetermined level of stability of the continuous glucose sensor has been determined at least in part by evaluating a level of oxygen.

34. The system of claim 33, wherein the computer system is configured output the sensor data to a display after the predetermined level of stability of the continuous glucose sensor has been determined.

35. The system of claim 33, wherein the computer system is configured output the sensor data to an insulin pump after the predetermined level of stability of the continuous glucose sensor has been determined.

36. The system of claim 33, wherein the computer system is configured output alerts configured to warn a user of a present and/or upcoming hypoglycemic and/or hyperglycemic event after the predetermined level of stability of the continuous glucose sensor has been determined.