Analyte sensor with lag compensation

• US 8,374,668 B1
• Filed: 10/23/2008
• Issued: 02/12/2013
• Est. Priority Date: 10/23/2007
• Status: Active Grant

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Hayter, Gary, Doniger, Kenneth J., Budiman, Erwin S.
• Primary Examiner(s): Natnithithadha, Navin
• Application Number:
  US12/257,356
• Time in Patent Office: 1,573 Days
• Field of Search: 600/309, 600345-366
• US Class Current: 600/347
• 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 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• 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 5/1486 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: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: G01N 33/48792 Data management, e.g. communication with processing unit for in vivo diagnostics A61B5/0002; transmission systems for measured values G08C
• CPC Class Codes: G16H 40/40 for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades

Abstract

In particular embodiments, methods, devices and systems including calibrating analyte data associated with a monitored analyte level received from an analyte sensor based on a reference measurement, determining a lag time constant associated with the calibrated analyte data, and performing lag correction of the calibrated analyte data based on the determined time lag constant are disclosed.

Claims

1. A computer implemented method, comprising:

receiving, using one or more processors, analyte data obtained from an analyte sensor;

determining, using the one or more processors, an analyte level of the user based at least in part on a nominal sensitivity associated with the analyte sensor and the received analyte data;

determining, using the one or more processors, a rate of change of the analyte level of the user;

determining, using the one or more processors, a lag time constant associated with the determined analyte level of the user;

performing, using the one or more processors, lag correction of the determined analyte level of the user based at least in part on the determined lag time constant;

incrementing, using the one or more processors, a count corresponding to the received analyte data;

updating, using the one or more processors, the determined rate of change of the analyte level;

determining, using the one or more processors, if the count has reached a predetermined count; and

when it is determined that the count has reached the predetermined count, modifying the lag corrected determined analyte level of the user based on the updated determined rate of change of the analyte level.

2. The method of claim 1 further including outputting, using the one or more processors, the lag corrected determined analyte level of the user.

3. The method of claim 1 wherein the analyte level is a glucose level.

4. The method of claim 1 wherein the analyte sensor is configured to measure the analyte level based on coulometry.

5. The method of claim 1 wherein the analyte sensor is configured to measure the analyte level based on amperometry.

6. The method of claim 1 wherein the nominal sensitivity associated with the analyte sensor is determined prior to use of the analyte sensor.

7. The method of claim 1 wherein performing lag correction of the determined analyte level of the user is further based at least in part on the determined rate of change of the analyte level.

8. The method of claim 1 wherein determining the analyte level of the user is further based at least in part on an average of at least two received analyte data.

9. The method of claim 1 wherein subsequently received analyte data is updated based on the modified lag corrected analyte level of the user.

10. A method, comprising:

receiving, using one or more processors, analyte data obtained from an analyte sensor;

determining, using the one or more processors, an analyte level of the user based at least in part on a nominal sensitivity associated with the analyte sensor and the received analyte data;

determining, using the one or more processors, a rate of change of the analyte level of the user;

determining, using the one or more processors, a time constant component and a time shift component associated with the determined analyte level of the user;

estimating, using the one or more processors, a lag time based on the determined time constant component and the time shift component;

incrementing, using the one or more processors, a count corresponding to the received analyte data;

updating, using the one or more processors, the determined rate of change of the analyte level;

determining, using the one or more processors, if the count has reached a predetermined count; and

when it is determined that the count has reached the predetermined count, modifying the lag corrected determined analyte level of the user based on the updated determined rate of change of the analyte level.

11. The method of claim 10 wherein subsequently received analyte data is updated based on the modified lag corrected analyte level of the user.

12. The method of claim 10 further including performing, using the one or more processors, lag correction of the determined analyte level of the user based on the estimated lag time.

13. The method of claim 12 further including outputting, using the one or more processors, the lag corrected determined analyte level of the user.

14. The method of claim 10 wherein the nominal sensitivity associated with the analyte sensor is determined prior to use of the analyte sensor.

15. The method of claim 10 wherein performing lag correction of the determined analyte level of the user is further based at least in part on the determined rate of change of the analyte level.

16. The method of claim 10 wherein determining the analyte level of the user is further based at least in part on an average of at least two received analyte data.

17. An apparatus, comprising:

one or more processors; and

a memory coupled to the one or more processors, the memory for storing instructions which, when executed by the one or more processors, causes the one or more processors to receive analyte data obtained from an analyte sensor, determine an analyte level of the user based at least in part on a nominal sensitivity associated with the analyte sensor and the received analyte data, determine a rate of change of the analyte level of the user, determine a time constant component and a time shift component associated with the determined analyte level of the user, estimate a lag time based on the determined time constant component and the time shift component, increment a count corresponding to the received analyte data, update the determined rate of change of the analyte level, determine if the count has reached a predetermined count, and when it is determined that the count has reached the predetermined count, modify the lag corrected determined analyte level of the user based on the updated determined rate of change of the analyte level.

18. The apparatus of claim 17 wherein the memory for storing instructions which, when executed by the one or more processes, causes the one or more processors to perform lag correction of the determined analyte level of the user based on the estimated lag time.

19. The apparatus of claim 17 wherein the memory for storing instructions which, when executed by the one or more processes, causes the one or more processors to perform lag correction of the determined analyte level of the user based at least in part on the determined rate of change of the analyte level.

20. The apparatus of claim 17 wherein the memory for storing instructions which, when executed by the one or more processes, causes the one or more processors to output the lag corrected determined analyte level of the user.

21. The apparatus of claim 17 wherein the analyte level of the user is further determined based at least in part on an average of at least two received analyte data.