Transcutaneous analyte sensor

• US 8,915,849 B2
• Filed: 02/03/2009
• Issued: 12/23/2014
• Est. Priority Date: 08/01/2003
• Status: Expired due to Term

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brauker, James H., Kamath, Apurv Ullas, Goode, Paul V.
• Primary Examiner(s): D'ANGELO, MICHAEL J
• Application Number:
  US12/364,786
• Publication Number:
  US 20090192724A1
• Time in Patent Office: 2,149 Days
• Field of Search: 600345-347, 600/365
• US Class Current: 600/365
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• 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 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• 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 5/14865 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 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots

Abstract

The present invention relates generally to systems and methods for measuring an analyte in a host. More particularly, the present invention relates to systems and methods for transcutaneous measurement of glucose in a host.

Claims

1. An electronic device for processing sensor data from a subcutaneous continuous glucose sensor, the device comprising:

a processor module configured to process sensor data from a subcutaneous continuous glucose sensor, the sensor data comprising a plurality of sensor data points; and

a computer readable memory comprising;

instructions configured to cause the processor module to determine a rate of change of the sensor data; and

instructions comprising a threshold rate of about 4 mg/dL/min, wherein the instruction are configured to allow the processor module to calibrate the sensor data using a reference glucose measurement when the rate of change is less than the threshold rate, but not allow the processor module to calibrate the sensor data using the reference glucose measurement when the rate of change is greater than the threshold rate.

2. The device of claim 1, wherein the calibration is based on a matched data pair formed by matching a sensor data point of the sensor data with the reference glucose measurement.

3. The device of claim 1, wherein the instructions configured to allow the processor module to calibrate the sensor data comprise instructions configured to cause the processor module to compensate for a time lag between the reference glucose measurement and a time-corresponding sensor data point.

4. The device of claim 1, wherein the instructions configured to allow the processor module to calibrate the sensor data comprise instructions configured to cause the processor module to evaluate the sensor data to determine a sensor break-in and to request the reference glucose measurement in response to the sensor break-in determination.

5. The device of claim 1, wherein the reference glucose measurement is obtained from a reference glucose monitor operatively and/or physically coupled to the electronic device.

6. The device of claim 1, wherein the instructions configured to allow the processor module to calibrate the sensor data comprise instructions configured to cause the processor module to determine a best matched data pair from a plurality of matched data pairs, wherein the plurality of matched data pairs comprise the reference glucose measurement matched with a plurality of individual sensor data points.

7. The device of claim 1, wherein the instructions configured to cause the processor module to calibrate the sensor data comprise instructions configured to cause the processor module to evaluate a clinical acceptability of the reference glucose measurement and a time-corresponding sensor data point based on a deviation of the time-corresponding sensor data point from the reference glucose measurement and a clinical risk associated with the deviation based on the glucose concentration indicated by the reference glucose measurement or the sensor data point.

8. The device of claim 7, wherein the instructions configured to cause the processor module to evaluate a clinical acceptability are based on a clinical error grid.

9. The device of claim 8, wherein the clinical error grid is a Clarke error grid.

10. The device of claim 1, wherein the sensor data is indicative of the concentration of glucose in a subcutaneous space of the host.

11. The device of claim 1, wherein the computer readable memory further comprises instructions configured to cause the processor module to prospectively calibrate the sensor data when calibration is allowed.

12. The device of claim 1, wherein the rate of change is calculated using calibrated sensor data.

13. The device of claim 1, wherein the computer readable memory further comprises instructions configured to cause the processor module to calculate real-time glucose concentration values based on the calibrated sensor data.

14. The device of claim 13, further comprising a user interface, wherein the computer readable memory further comprises instructions configured to cause the processor module to initiate display, on the user interface, of real-time glucose concentration information based on the calculated real-time glucose concentration values.

15. The device of claim 1, further comprising instructions configured to cause the processor module to estimate at least one projected glucose concentration value based at least in part on a linear extrapolation of calibrated sensor data and on a variation analysis.

16. The device of claim 15, further comprising instructions configured to cause the processor module to activate an alarm when a projected glucose concentration value is greater than a high threshold value or less than a low threshold value.

17. An electronic device for processing sensor data from a subcutaneous continuous glucose sensor, the device comprising:

a processor module configured to process sensor data from a subcutaneous continuous glucose sensor, the sensor data comprising a plurality of sensor data points; and

a computer readable memory comprising;

instructions configured to cause the processor module to determine a rate of change of the sensor data; and

instructions configured to cause the processor module to evaluate the rate of change of the sensor data against an acceptability criterion a threshold rate of 3.5 mg/dL/min. to determine whether a reference glucose measurement is acceptable for calibration of the sensor data, wherein the acceptability criterion allows for the instructions allow for calibration of the sensor data using the reference glucose measurement when the rate of change of the sensor data less than 3.5 mg/dL/min the threshold rate, but does not allow for calibration of the sensor data using the reference glucose measurement when the rate of change of the sensor data is above 3.5 mg/dL the threshold rate.

18. The device of claim 17, wherein the calibration is based on a matched data pair formed by matching a sensor data point of the sensor data with the reference glucose measurement.

19. The device of claim 17, further comprising instructions configured to cause the processor module to compensate for a time lag between the reference glucose measurement and a time-corresponding sensor data point.

20. The device of claim 17, further comprising instructions configured to cause the processor module to evaluate the sensor data to determine a sensor break-in and to request the reference glucose measurement in response to the sensor break-in determination.

21. The device of claim 17, wherein the reference glucose measurement is obtained from a reference glucose monitor operatively and/or physically coupled to the electronic device.

22. The device of claim 17, further comprising instructions configured to cause the processor module to determine a best matched data pair from a plurality of matched data pairs, wherein the plurality of matched data pairs comprise the reference glucose measurement matched with a plurality of individual sensor data points.

23. The device of claim 17, further comprising instructions configured to cause the processor module to evaluate a clinical acceptability of the reference glucose measurement and a time-corresponding sensor data point based on a deviation of the time-corresponding sensor data point from the reference glucose measurement and a clinical risk associated with the deviation based on the glucose concentration indicated by the reference glucose measurement or the sensor data point.

24. The device of claim 23, wherein the instructions configured to cause the processor module to evaluate a clinical acceptability are based on a clinical error grid.

25. The device of claim 24, wherein the clinical error grid is a Clarke error grid.

26. The device of claim 17, wherein the sensor data is indicative of the concentration of glucose in a subcutaneous space of the host.

27. The device of claim 17, wherein the computer readable memory further comprises instructions configured to cause the processor module to prospectively calibrate the sensor data when calibration is allowed.

28. The device of claim 17, wherein the rate of change is calculated using calibrated sensor data.

29. The device of claim 17, wherein the computer readable memory further comprises instructions configured to cause the processor module to calculate real-time glucose concentration values based on the calibrated sensor data.

30. The device of claim 29, further comprising a user interface, wherein the computer readable memory further comprises instructions configured to cause the processor module to initiate display, on the user interface, of real-time glucose concentration information based on the calculated real-time glucose concentration values.