SYSTEM AND METHODS FOR PROCESSING ANALYTE SENSOR DATA

• US 20100161269A1
• Filed: 12/08/2009
• Published: 06/24/2010
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Apurv Ullas, Brauker, James H., Goode, Paul V.
• Granted Patent: US 8,700,117 B2
• Time in Patent Office: Days
• US Class Current: 702/104
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2560/04 Constructional details of apparatus
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 3/10 Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/1433 provided with locking means details of syringes A61M5/315
• 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 5/14865 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: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: G01N 33/48707 by electrical means G01N33/49, G01N33/493 take precedence
• 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, 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 method for calibrating an analyte sensor, the method comprising:

receiving, with an electronic device, sensor data from an analyte sensor, wherein the sensor data comprises one or more sensor data points;

receiving reference data from a reference analyte monitor, wherein the reference data comprises one or more reference data points;

matching reference data to substantially time corresponding sensor data to form a calibration set, wherein the calibration set comprises one or more matched data pairs;

creating a conversion function based at least in part on the calibration set; and

converting the sensor data into calibrated data using the conversion function, wherein the sensor data points are smoothed using a data smoothing filter, and wherein the matching includes a time lag compensation based at least in part on a time delay introduced by the data smoothing filter.

2. The method of claim 1, wherein the received one or more sensor data points are smoothed sensor data points.

3. The method of claim 1, further comprising smoothing the one or more sensor data points using the data smoothing filter, whereby smoothed sensor data points are obtained.

4. The method of claim 1, wherein the time delay is variable based on the data smoothing filter.

5. The method of claim 1, wherein the time delay is approximately 10 minutes.

6. The method of claim 1, wherein the data smoothing filter is a recursive filter.

7. The method of claim 1, wherein the data smoothing filter is a non-recursive filter.

8. The method of claim 1, wherein the analyte sensor is a glucose sensor.

9. A method for calibrating an analyte sensor, the method comprising:

receiving, with an electronic device, sensor data associated with a data stream from an analyte sensor, wherein the sensor data comprises one or more sensor data points;

receiving reference data from a reference analyte monitor, wherein the reference data comprises one or more reference data points;

matching reference data to substantially time corresponding sensor data to form a calibration set, wherein the calibration set comprises one or more matched data pair;

creating a conversion function based at least in part on the calibration set; and

converting sensor data into calibrated data using the conversion function, wherein the matching includes a time lag compensation.

10. The method of claim 9, wherein the analyte sensor is a glucose sensor.

11. The method of claim 9, wherein the time lag compensation comprises predicting an estimated sensor data point, and wherein the matching comprises matching reference data to the estimated sensor data point.

12. The method of claim 9, wherein the substantial time correspondence is variable.

13. A system for calibrating an analyte sensor, the system comprising:

a sensor data receiving module configured to receive sensor data from an analyte sensor, wherein the sensor data comprises one or more sensor data points;

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

a processor module configured to match reference data to substantially time corresponding sensor data to form a calibration set comprising one or more matched data pairs, to create a conversion function based at least in part on the calibration set, and to convert sensor data into calibrated data using the conversion function, wherein the sensor data points are smoothed using a data smoothing filter, and wherein the processor module is configured to match the reference data and the sensor data using a time lag compensation based at least in part on a time delay introduced by the data smoothing filter.

14. The system of claim 13, wherein the one or more sensor data points are smoothed sensor data points.

15. The system of claim 13, wherein the processor module is configured to smooth the one or more sensor data points using the data smoothing filter, whereby the smoothed sensor data points are obtained.

16. The system of claim 13, wherein the time delay is variable based on the data smoothing filter.

17. The system of claim 13, wherein the time delay is approximately 10 minutes.

18. The system of claim 13, wherein the data smoothing filter is a recursive filter.

19. The system of claim 13, wherein the data smoothing filter is a non-recursive filter.

20. The system of claim 13, wherein the analyte sensor is a glucose sensor.

21. A system for calibrating an analyte sensor, the method comprising:

a sensor data receiving module configured to receive sensor data from an analyte sensor, wherein the sensor data comprises one or more sensor data points;

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

a processor module configured to match reference data to substantially time corresponding sensor data to form a calibration set, wherein the calibration set comprises one or more matched data pair, wherein the processor module is configured to create a conversion function based at least in part on the calibration set, and wherein the processor module is further configured to convert sensor data into calibrated data using the conversion function, wherein the processor module is further configured to match reference data to substantially time corresponding sensor data using a time lag compensation.

22. The system of claim 21, wherein the analyte sensor is a glucose sensor.

23. The system of claim 21, wherein the processor module is configured to predict an estimated sensor data point and match the reference data to the estimated sensor data point for the time lag compensation.

24. The system of claim 21, wherein the substantial time correspondence is variable.