Analyte Sensor with Time Lag Compensation

• US 20090198118A1
• Filed: 01/30/2009
• Published: 08/06/2009
• Est. Priority Date: 01/31/2008
• Status: Active Grant

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Doniger, Kenneth J., Hayter, Gary, Budiman, Erwin S.
• Granted Patent: US 8,473,022 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• 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 5/1495 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

Abstract

Methods and devices and systems for determining an analyte value are disclosed.

Claims

1. A method, comprising:

determining a predetermined time period characterized with a rate of change of an analyte level below a preset threshold;

defining a data set associated with a monitored analyte level within the predetermined time period;

determining a sensitivity value based on the defined data set;

applying the determined sensitivity value to signals associated with the monitored analyte level including the defined data set; and

estimating a time constant associated with an analyte sensor used to monitor the analyte level.

2. The method of claim 1 wherein the preset threshold associated with the rate of change of the analyte level is characterized by a quiescent state of the signals received from the analyte sensor.

3. The method of claim 1 including receiving a reference data, and applying the sensitivity value to the signals associated with the monitored analyte level based on the received reference data.

4. The method of claim 3 wherein the reference data includes a reference blood glucose measurement.

5. The method of claim 3 wherein the reference data is substantially time corresponding to one or more data in the defined data set.

6. The method of claim 1 including calibrating the signals associated with the monitored analyte level based at least in part on the estimated time constant.

7. The method of claim 1 including performing lag correction of the signals associated with the monitored analyte level based on the estimated time constant.

8. The method of claim 7 including calibrating the lag corrected signals to estimate the corresponding monitored glucose level.

9. A computer implemented method, comprising:

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.

10. The method of claim 9 including outputting the lag corrected calibrated analyte data.

11. The method of claim 9 wherein the reference measurement includes a blood glucose measurement.

12. The method of claim 9 wherein the reference measurement is obtained within a predetermined time period relative to the monitored analyte level.

13. The method of claim 12 wherein the predetermined time period is less than approximately 30 minutes or greater than approximately 30 minutes.

14. The method of claim 9 wherein calibrating the analyte data includes determining a sensitivity value associated with the analyte sensor.

15. The method of claim 14 wherein the sensitivity value includes a ratio of the analyte data and the corresponding reference measurement.

16. The method of claim 9 wherein the analyte level is glucose level.

17. The method of claim 9 wherein determining the rate of change includes determining a rate of increase or a rate of decrease of the monitored analyte level for a predefined time period.

18. The method of claim 9 further including determining a rate of change of the analyte level monitored by the analyte sensor.

19. The method of claim 18 wherein the rate of change of the analyte level is determined below a predetermined threshold.

20. The method of claim 9 wherein the analyte sensor is configured to measure the analyte level based on coulometry.

21. The method of claim 9 wherein the analyte sensor is configured to measure the analyte level based on amperometry.

22. An apparatus, comprising:

a data communication interface;

one or more processors operatively coupled to the data communication interface; and

a memory for storing instructions which, when executed by the one or more processors, causes the one or more processors to determine a predetermined time period characterized with a rate of change of an analyte level below a preset threshold, define a data set associated with a monitored analyte level within the predetermined time period, determine a sensitivity value based on the defined data set, apply the determined sensitivity value to signals associated with the monitored analyte level including the defined data set, and estimate a time constant associated with an analyte sensor used to monitor the analyte level.