SYSTEM AND METHODS FOR PROCESSING ANALYTE SENSOR DATA

• US 20100174167A1
• Filed: 12/16/2009
• Published: 07/08/2010
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Apurv Ullas, Brauker, James H., Carr-Brendel, Victoria E., Goode, Paul V. JR.
• Granted Patent: US 8,588,882 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 processing sensor data from an analyte sensor, comprising:

receiving, with an electronic device, sensor data from an analyte sensor, wherein the sensor data comprises a plurality of sensor data points;

calculating a change in a baseline associated with the received plurality of sensor data points over a predetermined time period or a change in a sensitivity associated with the received plurality of sensor data points over a predetermined time period;

determining a level of stability of the analyte sensor based at least in part on a change selected from group consisting of the change in the baseline, the change in the sensitivity, and combinations thereof; and

controlling an output in response to the determined level of stability.

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

3. The method of claim 1, wherein controlling an output comprises requesting reference data.

4. The method of claim 3, wherein the reference data comprises in vitro blood glucose measurement data.

5. The method of claim 3, further comprising calibrating the analyte sensor based at least in part on the reference data.

6. The method of claim 1, wherein determining a level of stability comprises determining a stability threshold for displaying real time sensor data when a change meets at least one predetermined criteria, wherein the change is selected from the group consisting of the change the baseline, the change the sensitivity, and combinations thereof.

7. The method of claim 6, wherein controlling an output comprises displaying real time calibrated sensor data.

8. The method of claim 1, wherein determining a level of stability comprises determining an instability threshold for suspending real time display of sensor data when a change meets at least one predetermined criteria, wherein the change is selected from the group consisting of the change in the baseline, the change in the sensitivity, and combinations thereof.

9. The method of claim 8, wherein controlling an output comprises suspending display of real time calibrated sensor data.

10. A system for processing sensor data from an analyte sensor, comprising:

an analyte sensor configured to measure an in vivo analyte concentration; and

a data processing device operatively coupled to the analyte sensor and configured to intermittently receive sensor data points associated with the analyte sensor, wherein the data processing device is further configured to determine a level of stability of the analyte sensor based at least in part on a change selected from the group consisting of a change in a baseline associated with the received sensor data points over a predetermined time period, a change in a sensitivity associated with the received sensor data points over a predetermined time period, and combinations thereof, wherein the data processing device is further configured to control an output in response to the determined level of stability.

11. The system of claim 10, wherein the analyte sensor is a glucose sensor.

12. The system of claim 10, wherein control of the output is performed at least in part by requesting reference data.

13. The system of claim 12, wherein the reference data comprises in vitro blood glucose measurement data.

14. The system of claim 12, further comprising a calibration module configured to calibrate the analyte sensor based at least in part on the determined sensitivity value.

15. The system of claim 10, wherein the data processing device is configured to determine a stability threshold for displaying real time sensor data when a change meets at least one predetermined criteria, wherein the change is selected from the group consisting of the change in the baseline, the change in the sensitivity, and combinations thereof.

16. The system of claim 15, wherein the data processing device is configured to control an output by displaying real time calibrated sensor data.

17. The system of claim 10, wherein the data processing device is configured to determine an instability threshold for suspending real time display of sensor data when a change meets at least one predetermined criteria, wherein the change is selected from the group consisting of the change in the baseline, the change in the sensitivity, and combinations thereof.

18. The system of claim 15, wherein the data processing device is configured to control an output by suspending display of real time calibrated sensor data.

19. A method for initializing a glucose sensor, comprising:

analyzing, with an electronic device, a glucose related signal from a glucose sensor to determine a sensor stability, wherein at least a portion of the glucose sensor is beneath a skin surface of a host; and

reporting glucose related information when the sensor is determined to be stable, wherein the glucose related information is not reported prior to determining that the sensor is stable.

20. The method of claim 19, wherein sensor stability is determined using reference data.

21. The method of claim 20, wherein the reference data is obtained by sampling blood of the individual.

22. The method of claim 20, wherein the reference data is obtained from a glucose test strip.

23. The method of claim 19, further comprising analyzing the sensor signal to determine whether a sensor sensitivity variability exists that exceeds a predetermined threshold, over a predetermined time period.

24. The method of claim 19, wherein reporting glucose related information is performed after about one hour following the insertion of the sensor.