SYSTEM AND METHODS FOR PROCESSING ANALYTE SENSOR DATA FOR SENSOR CALIBRATION

• US 20130060112A1
• Filed: 09/07/2012
• Published: 03/07/2013
• Est. Priority Date: 03/10/2005
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Pryor, Jack, Kamath, Apurv Ullas, Goode, Paul V., Brauker, James H.
• Granted Patent: US 9,314,196 B2
• Time in Patent Office: Days
• US Class Current: 600/365
• 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 calibrating a continuous analyte sensor, comprising:

receiving sensor data from a continuous analyte sensor, wherein the sensor data is indicative of a glucose concentration in a host;

determining a conversion function, using a processor module, wherein the conversion function comprises a slope and a baseline, wherein the slope is representative of a sensor sensitivity, and wherein at least one of the slope or the baseline is determined based on prior distribution information; and

converting the sensor data using the conversion function.

2. The method of claim 1, wherein determining the conversion function comprises determining the slope based on prior slope distribution information.

3. The method of claim 2, wherein determining the slope comprises selecting a most probable slope from a distribution of slopes based on the prior slope distribution information.

4. The method of claim 1, wherein determining the conversion function comprises determining the baseline based on prior baseline distribution information.

5. The method of claim 2, wherein determining the baseline comprises selecting a most probable baseline from a distribution of baselines based on the prior baseline distribution information.

6. The method of claim 1, wherein determining the conversion function comprises determining the slope and the baseline based on prior slope and baseline distribution information.

7. The method of claim 6, wherein determining the slope and the baseline comprises selecting a most probable slope and baseline from a distribution of slopes and baselines based on the prior slope and baseline distribution information.

8. The method of claim 7, wherein selecting the most probable slope and baseline comprises selecting a slope and baseline closest to the maximum joint probability of both the slope and baseline distributions.

9. The method of claim 1, where determining the conversion function comprises selecting one of a plurality of possible calibration lines having various baselines and slopes based on prior information indicative of typical distribution of slopes and/or baselines.

10. The method of claim 1, wherein the slope is determined, at least in part, based on in-vitro slope information determined by a benchtop calibration process.

11. The method of claim 1, further comprising receiving reference data from a reference analyte monitor, wherein the slope is determined, at least in part, based on the reference analyte value.

12. The method of claim 1, wherein the prior distribution information is derived from in vivo testing of at least one other continuous glucose sensor or in vitro testing.

13. The method of claim 1, further comprising displaying the converted sensor data is substantially real time.

14. The method of claim 1, wherein the analyte is glucose.

15. A system for calibrating a continuous analyte sensor, comprising:

a continuous analyte sensor configured to provide sensor data indicative of an analyte concentration in a host; and

a processor module configured to determine a conversion function, wherein the conversion function comprises a slope and a baseline, wherein the slope is representative of a sensor sensitivity, wherein at least one of the slope or the baseline is determined based on prior distribution information, and wherein the processor module is configured to convert the sensor data using the conversion function.

16. The system of claim 15, wherein the processor module is configured to determine the slope based on prior slope distribution information.

17. The system of claim 16, wherein the processor module is configured to determine the slope by selecting a most probable slope from a distribution of slopes based on the prior slope distribution information.

18. The system of claim 15, wherein the processor module is configured to determine the baseline based on prior baseline distribution information.

19. The system of claim 15, wherein the processor module is configured to determine the baseline by selecting a most probable baseline from a distribution of baselines based on the prior baseline distribution information.

20. The system of claim 15, wherein the processor module is configured to determine the slope and the baseline based on prior slope and baseline distribution information.

21. The system of claim 15, wherein the processor module is configured to determine the slope and the baseline by selecting a most probable slope and baseline from a distribution of slopes and baselines based on the prior slope and baseline distribution information.

22. The system of claim 21, wherein the processor module is configured to select the most probable slope and baseline by selecting a slope and baseline closest to the maximum joint probability of both the slope and baseline distributions.

23. The system of claim 15, wherein the processor module is configured to determine the conversion function by selecting one of a plurality of possible calibration lines having various baselines and slopes based on prior information indicative of typical distribution of slopes and/or baselines.

24. The system of claim 15, wherein the slope is determined, at least in part, based on in-vitro slope information determined by a benchtop calibration process.

25. The system of claim 15, wherein the processor module is configured to receive reference data from a reference analyte monitor, and wherein the slope is determined, at least in part, based on the reference analyte value.

26. The system of claim 15, wherein the prior distribution information is derived from in vivo testing of at least one other continuous glucose sensor or in vitro testing.

27. The system of claim 15, wherein the processor module is configured to display the converted sensor data in substantially real time.

28. The system of claim 15, wherein the analyte is glucose.