SYSTEM AND METHODS FOR PROCESSING ANALYTE SENSOR DATA

• US 20080194937A1
• Filed: 04/14/2008
• Published: 08/14/2008
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brauker, James H., Carr-Brendel, Victoria, Goode, Paul V., Kamath, Apurv U.
• Granted Patent: US 7,599,726 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 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 data from a glucose sensor, the method comprising:

receiving sensor data from a glucose sensor, including one or more sensor data points;

receiving reference data, including one or more reference data points; and

calibrating the sensor data using the reference data after the glucose sensor has reached a predetermined level of stability.

2. The method of claim 1, wherein the step of calibrating is only performed if the glucose sensor reaches a predetermined level of stability.

3. The method of claim 1, determining a level of stability by evaluating said one or more reference data points against one or more time-corresponding sensor data points.

4. The method of claim 1, wherein the step of receiving reference data comprises receiving data obtained from a blood glucose test.

5. The method of claim 1, wherein the step of receiving reference data comprises receiving an internal wired communication from a reference glucose monitor.

6. The method of claim 1, determining a level of stability by evaluating a frequency content of the sensor data.

7. A system for calibrating data from a glucose sensor, the system comprising:

a sensor data module configured to receive sensor data from the glucose sensor, including one or more sensor data points;

a reference input module configured to receive one or more reference glucose points from a reference glucose monitor; and

a processor module configured to calibrate the glucose sensor after the glucose sensor has reached a predetermined level of stability.

8. The system of claim 7, wherein processor module is configured to calibrate the glucose sensor only after the glucose sensor reaches a predetermined level of stability.

9. The system of claim 7, wherein the processor module is configured to determine a level of stability of the glucose sensor by evaluating one or more reference data points against a substantially time-corresponding sensor data point.

10. The system of claim 7, wherein the one or more reference data points are obtained from a blood glucose test.

11. The system of claim 7, wherein the one or more reference data points are obtained from a reference glucose monitor integral with said system.

12. The system of claim 7, wherein the processor module is configured to determine a level of stability by evaluating a frequency content of the sensor data.

13. A method for calibrating a continuous glucose sensor, the sensor comprising:

receiving one or more sensor data points from a continuous glucose sensor; and

prompting a user for reference glucose data after a predetermined level of stability of the continuous glucose sensor has been reached.

14. The method of claim 13, determining a level of stability by evaluating physiological information.

15. The method of claim 14, wherein the physiological information comprises time of day, oxygen concentration and/or postural effect.

16. The method of claim 14, determining a predetermined level of stability by evaluating a patient-entered event.

17. The method of claim 16, wherein the patient-entered event comprises meal information and/or exercise information.

18. The method of claim 14, determining a level of stability by evaluating a frequency content of the sensor data.

19. A system for calibrating a continuous glucose sensor, the sensor comprising:

a sensor data module operatively linked to a continuous glucose sensor and configured to receive one or more sensor data points from said sensor; and

a processor module programmed to prompt a user for reference glucose data after a predetermined level stability of the continuous glucose sensor has been reached.

20. The system of claim 19, wherein the processor module is configured to determine a level of stability by evaluating physiological information.

21. The system of claim 20, wherein the physiological information comprises time of day, oxygen concentration and/or postural effect.

22. The system of claim 20, wherein the processor module is configured to determine a level of stability by evaluating a patient-entered event.

23. The system of claim 22, wherein the patient-entered event comprises meal information and/or exercise information.

24. The system of claim 20, wherein the processor module is configured to determine a level of stability by evaluating a frequency content of the sensor data.