Method, system and computer program product for real-time detection of sensitivity decline in analyte sensors

• US 8,135,548 B2
• Filed: 10/26/2007
• Issued: 03/13/2012
• Est. Priority Date: 10/26/2006
• Status: Active Grant

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated), University of Virginia Patent Foundation (University of Virginia)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated), University of Virginia Patent Foundation (University of Virginia)
• Inventors: Breton, Marc D., Kovatchev, Boris P., Budiman, Erwin S., Doniger, Kenneth J.
• Primary Examiner(s): Lau, Tung S
• Application Number:
  US11/925,689
• Publication Number:
  US 20080172205A1
• Time in Patent Office: 1,600 Days
• Field of Search: 702/57
• US Class Current: 702/57
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• 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 5/14532 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 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: G16H 10/40 for data related to laboratory analysis, e.g. patient specimen analysis
• CPC Class Codes: G16H 40/60 for the operation of medical equipment or devices
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: H04B 17/00 Monitoring; Testing of line transmission systems H04B3/46; arrangements for monitoring or testing transmission systems employing electromagnetic waves other than radio waves H04B10/07

Abstract

A computer implemented method for receiving a plurality of analyte sensor related signals, determining a probability of signal attenuation associated with the received plurality of analyte sensor related signals, verifying the presence of signal attenuation when the determined probability exceeds a predetermined threshold level, and generating a first output signal associated with the verification of the presence of signal attenuation is provided. Also provided are systems and kits.

Claims

1. A computer implemented method for detecting early signal attenuation in a glucose sensor, comprising:

receiving a first plurality of glucose sensor related signals within a first predetermined time period after insertion of the glucose sensor into a user, wherein the first predetermined time period occurs within the first 24 hours of insertion;

determining a sensitivity of the glucose sensor based on the first plurality of glucose sensor related signals and a blood glucose measurement;

determining a probability of early signal attenuation associated with the first plurality of glucose sensor related signals;

determining a sensitivity ratio based on the determined sensitivity of the glucose sensor divided by a nominal sensitivity, the nominal sensitivity determined at the time the glucose sensor is manufactured;

receiving a second plurality of glucose sensor related signals during a second predetermined time period when the determined probability does not exceed a first predetermined threshold level, wherein the second predetermined time period is offset from the first predetermined time period by a predetermined offset time;

verifying the presence of early signal attenuation when the determined probability exceeds the first predetermined threshold level and the determined sensitivity ratio is less than a second predetermined threshold level; and

generating a first output signal with a processor associated with the verification of the presence of early signal attenuation.

2. The method of claim 1 wherein determining the probability of early signal attenuation includes:

determining one or more characteristics associated with the first plurality of glucose sensor related signals; and

wherein each of the one or more characteristics has a corresponding predetermined coefficient.

3. The method of claim 1 wherein the first predetermined threshold level is user defined.

4. The method of claim 1 wherein when the determined probability does not exceed the first predetermined threshold level, generating a second output signal associated with absence of early signal attenuation condition.

5. The method of claim 1 wherein verifying the presence of early signal attenuation includes:

selecting an early signal attenuation threshold level; and

confirming the presence of early signal attenuation based at least in part on a comparison of the determined sensitivity and the selected early signal attenuation threshold level.

6. The method of claim 1 wherein the sensitivity of the glucose sensor is determined as a ratio of the average of the first plurality of glucose sensor related signals and the blood glucose measurement.

7. The method of claim 1 wherein the predetermined offset time is equivalent to the first predetermined time period.

8. The method of claim 1 wherein the predetermined offset time is less than the first predetermined time period.

9. The method of claim 1 wherein a time duration of the first predetermined time period is equivalent to a time duration of the second predetermined time period.

10. The method of claim 1 further comprising:

determining a second probability of early signal attenuation associated with the second plurality of glucose sensor related signals;

verifying the presence of early signal attenuation in the second plurality of glucose sensor related signals when the determined second probability exceeds the first predetermined threshold level; and

generating the first output signal associated with the verification of the presence of early signal attenuation.

11. The method of claim 2 wherein the determined one or more characteristics includes one or more of a mean value associated with the first plurality of glucose related signals, an average slope associated with the first plurality of glucose related signals, a standard deviation associated with the first plurality of glucose related signals, an average elapsed time from insertion of the glucose sensor, or a variance of the first plurality of glucose related signals.

12. The method of claim 5 wherein the early signal attenuation threshold level is associated with a blood glucose measurement.

13. The method of claim 5 wherein confirming the presence of early signal attenuation includes determining that the sensitivity of the glucose sensor is less than the selected early signal attenuation threshold level.

14. The method of claim 12 wherein the blood glucose measurement include a capillary blood glucose sampling.

15. An apparatus, comprising:

a data storage unit; and

a processing unit operatively coupled to the data storage unit configured to receive a first plurality of glucose sensor related signals within a first predetermined time period after insertion of the glucose sensor into a user, wherein the first predetermined time period occurs within the first 24 hours of insertion, determine a sensitivity of the glucose sensor based on the first plurality of glucose sensor related signals and a blood glucose measurement, determine a probability of early signal attenuation associated with the first plurality of glucose sensor related signals, determine a sensitivity ratio based on the determined sensitivity of the glucose sensor divided by a nominal sensitivity, the nominal sensitivity determined at the time the glucose sensor is manufactured, receive a second plurality of glucose sensor related signals during a second predetermined time period when the determined probability does not exceed a first predetermined threshold level, wherein the second predetermined time period is offset from the first predetermined time period by a predetermined offset time, verify the presence of early signal attenuation when the determined probability exceeds the first predetermined threshold level and the determined sensitivity ratio is less than a second predetermined threshold level, and generate a first output signal associated with the verification of the presence of early signal attenuation.

16. The apparatus of claim 15 wherein the processing unit configured to determine the probability of early signal attenuation is configured to determine one or more characteristics associated with the first plurality of glucose sensor related signals, and to apply a predetermined coefficient to the first plurality of glucose sensor related signals.

17. The apparatus of claim 15 wherein the first predetermined threshold level is user defined.

18. The apparatus of claim 15 wherein when the determined probability does not exceed the first predetermined threshold level, the processing unit is further configured to generate a second output signal associated with absence of early signal attenuation condition.

19. The apparatus of claim 15 wherein the processing unit is further configured to select an early signal attenuation threshold level and confirm the presence of early signal attenuation based at least in part on a comparison of the determined sensitivity and the selected early signal attenuation threshold level.

20. The apparatus of claim 15 wherein the sensitivity of the glucose sensor is determined as a ratio of the average of the first plurality of glucose sensor related signals and the blood glucose measurement.

21. The apparatus of claim 15 including a user output unit operatively coupled to the processing unit to display the first output signal.

22. The apparatus of claim 16 wherein the determined one or more characteristics includes one or more mean value associated with the glucose sensor related signals, the least square slope associated with the glucose sensor related signals, a standard deviation associated with the glucose sensor related signals, an average elapsed time from positioning the analyte glucose sensor, or a variance about a least squares slope associated with the glucose sensor related signals.

23. The apparatus of claim 19 wherein the early signal attenuation threshold level is associated with a blood glucose measurement.

24. The apparatus of claim 19 wherein the processing unit is further configured to determine that the sensitivity of the glucose sensor is less than the selected early signal attenuation threshold level.

25. The apparatus of claim 23 wherein the blood glucose measurement include a capillary blood glucose sampling.

26. A system for detecting early signal attenuation in a glucose sensor, comprising:

a glucose sensor for transcutaneous positioning through a skin layer of a user; and

a data processing device operatively coupled to the glucose sensor, the data processing device configured to receive a first plurality of glucose sensor related signals within a first predetermined time period after insertion of the glucose sensor into the user, wherein the first predetermined time period occurs within the first 24 hours of insertion, determine a sensitivity of the glucose sensor based on the first plurality of glucose sensor related signals and a blood glucose measurement, determine a probability of the early signal attenuation associated with the first plurality of glucose sensor related signals, determine a sensitivity ratio based on the determined sensitivity of the glucose sensor divided by a nominal sensitivity, the nominal sensitivity determined at the time the glucose sensor is manufactured, receive a second plurality of glucose sensor related signals during a second predetermined time period when the determined probability does not exceed a first predetermined threshold level, wherein the second predetermined time period is offset from the first predetermined time period by a predetermined offset time, verify the presence of early signal attenuation when the determined probability exceeds the first predetermined threshold level and the determined sensitivity ratio is less than a second predetermined threshold level, and generate a first output signal associated with the verification of the presence of early signal attenuation.

27. The system of claim 26 wherein the data processing device includes a user interface to output the first output signal associated with the verification of the presence of early signal attenuation associated with the glucose sensor.