System and methods for processing analyte sensor data

• US 8,788,006 B2
• Filed: 12/11/2009
• Issued: 07/22/2014
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Apurv Ullas, Goode, Paul V. Jr., Brauker, James H.
• Primary Examiner(s): D'ANGELO, MICHAEL J
• Application Number:
  US12/636,540
• Publication Number:
  US 20100168541A1
• Time in Patent Office: 1,684 Days
• Field of Search: 600/309, 600/316, 600345-347, 600/365
• US Class Current: 600/345
• 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 5/1495 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 method for calibrating a substantially continuous analyte sensor, the method comprising:

receiving a sensor data stream comprising one or more sensor data points from a substantially continuous analyte sensor;

receiving reference data comprising one or more reference data points from a reference analyte monitor;

using a processor module to form at least two matched data pairs by matching reference analyte data to substantially time corresponding sensor data;

using the processor module to form a calibration set comprising the at least two matched data pairs;

using the processor module to create a conversion function based on the calibration set;

using the processor module to convert sensor data into calibrated sensor data using the conversion function;

subsequently receiving an additional reference data point and creating a new matched data pair using the additional reference data point;

using the processor module to evaluate the calibration set with the new matched data pair to ensure the calibration set has substantially distributed high and low matched data pairs over a predetermined time range; and

using the processor module to subsequently modify the conversion function based on the evaluation.

2. The method of claim 1, wherein receiving the sensor data stream comprises receiving a data stream from an implantable analyte sensor.

3. The method of claim 1, wherein receiving the sensor data stream comprises receiving a data stream that has been algorithmically smoothed.

4. The method of claim 1, wherein receiving the sensor data stream comprises algorithmically smoothing the data stream.

5. The method of claim 1, wherein receiving reference data comprises downloading reference data via a wireless connection.

6. The method of claim 1, wherein receiving reference data comprises downloading reference data via a wired connection.

7. The method of claim 1, wherein receiving reference data from a reference analyte monitor comprises receiving within a receiver internal communication from a reference analyte monitor integral with the receiver.

8. The method of claim 1, wherein the reference analyte monitor is configured for self-monitoring of a blood analyte.

9. The method of claim 1, wherein using the processor module to create a conversion function comprises performing a linear regression.

10. The method of claim 1, wherein using the processor module to create a conversion function performing a non-linear regression.

11. The method of claim 1, wherein using the processor module to create a conversion function utilizes from one matched data pair to six matched data pairs.

12. The method of claim 1, wherein using the processor module to create a conversion function utilizes at least two matched data pairs.

13. The method of claim 1, wherein the processor module is incorporated into sensor electronics, receiver electronics or both.

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

a sensor data receiving module configured to receive a sensor data stream comprising one or more sensor data points from a substantially continuous analyte sensor;

a reference data receiving module configured to receive reference data comprising one or more reference data points from a reference analyte monitor; and

a processor module configured to form at least two matched data pairs by matching reference analyte data to substantially time corresponding sensor data, wherein the processor module is configured to form a calibration set comprising the at least two matched data pairs, wherein the processor module is further configured to create a conversion function based on the calibration set, wherein processor module is configured to convert sensor data into calibrated sensor data using the conversion function, wherein the processor module is configured to subsequently receive an additional reference data point and create a new matched data pair using the additional reference data point, wherein the processor module is further configured to evaluate the calibration set with the new matched data pair to ensure the calibration set has substantially distributed high and low matched data pairs over a predetermined time range, and wherein the processor module is further configured to subsequently modify the conversion function based on the evaluation.

15. The system of claim 14, wherein the sensor data stream is received from an implantable analyte sensor.

16. The system of claim 14, wherein the sensor data stream is algorithmically smoothed.

17. The system of claim 14, wherein the processor module is configured to algorithmically smooth said sensor data stream.

18. The system of claim 14, wherein the reference data receiving module is configured to download the reference data using a wireless connection.

19. The system of claim 14, wherein the reference data receiving module is configured to download the reference data using a wired connection.

20. The system of claim 14, wherein the reference data receiving module is configured to receive the reference data a receiver internal communication from a reference analyte monitor integral with said receiver.

21. The system of claim 14, wherein the reference analyte monitor is configured for self-monitoring of a blood analyte.

22. The system of claim 14, wherein the processor module is configured to create the conversion function using a linear regression.

23. The system of claim 14, wherein the processor module is configured to create the conversion function using a non-linear regression.

24. The system of claim 14, wherein the conversion function is created using from one matched data pair to six matched data pairs.

25. The system of claim 14, wherein the conversion function is created using at least two matched data pairs.

26. The system of claim 14, wherein the processor module is incorporated in sensor electronics, receiver electronics or both.