Sensor fault detection using analyte sensor data pattern comparison

• US 10,076,285 B2
• Filed: 03/13/2014
• Issued: 09/18/2018
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories)
• Inventors: Ou, Junli, Budiman, Erwin Satrya
• Primary Examiner(s): Natnithithadha, Navin
• Assistant Examiner(s): MESSERSMITH, ERIC J
• Application Number:
  US14/771,804
• Publication Number:
  US 20160022221A1
• Time in Patent Office: 1,650 Days
• CPC Class Codes: A61B 2560/0228 using calibration standards
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: A61B 5/7271 Specific aspects of physiological measurement analysis A61B5/316, A61B5/349 and A61B5/374 take precedence
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

Analyte sensor faults are detected. Datasets of glucose values sensor electronics are coupled to a glucose sensor in fluid contact with interstitial fluid under a skin surface. Baseline median glucose value and glucose variability values are computed, based on the first dataset. A baseline data point is stored. Evaluation median glucose value and variability are computed, based on the second dataset of glucose values. An evaluation data point is stored. A magnitude of a vector that extends between the baseline data point and the evaluation data point is computed. A component of the magnitude of the vector that is parallel to a hypoglycemia risk contour line is computed and compared to a predefined threshold value. An indication that a sensor fault has been detected if the component is greater than a threshold is displayed.

Claims

1. A computer-implemented method, comprising:

storing a baseline data point in a memory wherein the baseline data point is representative of a first point on a glucose control grid;

storing an evaluation data point in the memory wherein the evaluation data point is representative of a second point on the glucose control grid;

computing a magnitude of a vector that would extend between the baseline data point and the evaluation data point if plotted on the glucose control grid;

defining a gradient function over an area of the glucose control grid and determining gradient contour lines around the baseline data point and the evaluation data point;

computing a component of the magnitude of the vector between the baseline data point and the evaluation data point that is parallel to a contour line of the defined gradient function;

comparing the component of the magnitude of the vector to a first predefined threshold value;

displaying, on a system display, an indication that a sensor fault has been detected if the component of the magnitude of the vector is greater than the first predefined threshold value; and

displaying, on the system display, an indication that the sensor fault has not been detected if the component of the magnitude of the vector is less than the first predefined threshold value.

2. The computer-implemented method of claim 1, wherein the baseline data point is determined based on using a baseline median glucose value and a baseline glucose variability value as coordinates for the baseline data point;

and further

wherein the baseline median glucose value and the baseline glucose variability value are computed by a processor based on a first dataset of glucose values received from a first data communication from sensor electronics operatively coupled to a transcutaneously positioned glucose sensor.

3. The computer-implemented method of claim 2, wherein the evaluation data point is determined based on using an evaluation median glucose value and an evaluation glucose variability value as coordinates for the evaluation data point;

and further

wherein the evaluation median glucose value and the evaluation glucose variability value are computed using the processor based on a second dataset of glucose values received from a second data communication from the sensor electronics operatively coupled to the transcutaneously positioned glucose sensor, where the second dataset of glucose values includes glucose values that are not in the first dataset of glucose values.

4. The computer-implemented method of claim 1, wherein displaying, on the system display, the indication that the sensor fault has been detected further includes prompting a user to indicate whether to maintain use of a glucose sensor.

5. The computer-implemented method of claim 4, wherein displaying, on the system display, the indication that the sensor fault has been detected further includes requesting a reference glucose measurement for validation.

6. The computer-implemented method of claim 5, wherein displaying, on the system display, the indication that the sensor fault has been detected further includes comparing sensor output to the reference glucose measurement relative to a second predefined threshold value.

7. The computer-implemented method of claim 5, wherein displaying, on the system display, the indication that the sensor fault has been detected further includes displaying, on the system display, an indication to remove the glucose sensor if the component of the magnitude of the vector is greater than a second predefined threshold value.

8. A system for determining analyte concentration in blood based on analyte concentration measured in interstitial fluid, the system comprising:

a processor; and

a memory coupled to the processor, the memory storing processor executable instructions to;

store a baseline data point in the memory wherein the baseline data point is representative of a first point on an analyte control grid;

store an evaluation data point in the memory wherein the evaluation data point is representative of a second point on the analyte control grid;

compute a magnitude of a vector that would extend between the baseline data point and the evaluation data point if plotted on the analyte control grid;

define a gradient function over an area of the analyte control grid and determine gradient contour lines around the baseline data point and the evaluation data point;

compute a component of the magnitude of the vector between the baseline data point and the evaluation data point that is parallel to a contour line of the defined gradient function;

compare the component of the magnitude of the vector to a first predefined threshold value;

display, on a system display, an indication that a sensor fault has been detected if the component of the magnitude of the vector is greater than the first predefined threshold value; and

display, on the system display, an indication that the sensor fault has not been detected if the component of the magnitude of the vector is less than the first predefined threshold value.

9. The system of claim 8, wherein the memory is further configured to store processor executable instructions to:

receive a first dataset of analyte values from sensor electronics operatively coupled to a transcutaneously positioned analyte sensor;

compute a baseline median analyte value based on the first dataset of analyte values;

compute a baseline analyte variability value based on the first dataset of analyte values; and

determine the baseline data point based on using the baseline median analyte value and the baseline analyte variability value as coordinates for the baseline data point on the analyte control grid.

10. The system of claim 9, wherein the memory is further configured to store processor executable instructions to:

receive a second dataset of analyte values from the sensor electronics where the second dataset of analyte values includes analyte values that are not in the first dataset of analyte values;

compute an evaluation median analyte value based on the second dataset of analyte values;

compute an evaluation analyte variability value based on the second dataset of analyte values; and

determine the evaluation data point based on using the evaluation median analyte value and the evaluation analyte variability value as coordinates for the evaluation data point on the analyte control grid.

11. The system of claim 8, wherein the memory is further configured to store processor executable instructions to display, on the system display, the indication that the sensor fault has been detected and further includes an instruction to prompt a user to indicate whether to maintain use of a sensor.

12. The system of claim 11, wherein the instruction to display, on the system display, the indication that the sensor fault has been detected further includes an instruction to request a reference glucose measurement for validation.

13. The system of claim 12, wherein the instruction to display, on the system display, the indication that the sensor fault has been detected further includes an instruction to compare sensor output to the reference glucose measurement relative to a second predefined threshold value.

14. The system of claim 13, wherein the instruction to display, on the system display, the indication that the sensor fault has been detected further includes an instruction to display, on the system display, an indication to remove the sensor if the component of the magnitude of the vector is greater than the second predefined threshold value.

15. A computer-implemented method, comprising:

storing an evaluation data point representative of a first point on a glucose control grid;

storing a baseline data point representative of a second point on the glucose control grid;

computing a magnitude of a vector that extends between the baseline data point and the evaluation data point;

defining a gradient function over an area of the glucose control grid including determining at least one gradient contour line around the baseline data point and the evaluation data point;

computing a component of the magnitude of the vector between the baseline data point and the evaluation data point that is parallel to a contour line of the defined gradient function;

comparing the component of the magnitude of the vector to a first predefined threshold value;

displaying, on a system display, an indication that an early signal attenuation (ESA) fault has been detected if the component of the magnitude of the vector is greater than the first predefined threshold value; and

displaying, on the system display, an indication that the early signal attenuation (ESA) fault has not been detected if the component of the magnitude of the vector is less than the first predefined threshold value.

16. The computer-implemented method of claim 15, further comprising:

receiving during an early wear period, a first dataset of glucose values from sensor electronics operatively coupled to a transcutaneously positioned glucose sensor;

computing an evaluation median glucose value based on the first dataset of glucose values;

computing an evaluation glucose variability value based on the first dataset of glucose values; and

determining the evaluation data point based on using the evaluation median glucose value and the evaluation glucose variability value as coordinates for the evaluation data point on the glucose control grid.

17. The computer-implemented method of claim 16, further comprising:

receiving after the early wear period a second dataset of glucose values from the sensor electronics where the second dataset of glucose values does not include glucose values that are also in the first dataset of glucose values;

computing a baseline median glucose value based on the second dataset of glucose values;

computing a baseline glucose variability value based on the second dataset of glucose values; and

determining the baseline data point based on using the baseline median glucose value and the baseline glucose variability value as coordinates for the baseline data point on the glucose control grid.

18. The computer-implemented method of claim 15, wherein displaying, on the system display, the indication that the early signal attenuation (ESA) fault has been detected further includes prompting a user whether to maintain use of a glucose sensor.

19. The computer-implemented method of claim 18, wherein displaying, on the system display, the indication that the early signal attenuation (ESA) fault has been detected further includes requesting a reference glucose measurement for validation.

20. The computer-implemented method of claim 19, wherein displaying, on the system display, the indication that the early signal attenuation (ESA) fault has been detected further includes comparing sensor output to the reference glucose measurement relative to a second predefined threshold value.

21. The computer-implemented method of claim 20, wherein displaying, on the system display, the indication that the early signal attenuation (ESA) fault has been detected further includes displaying, on the system display, an indication that a first dataset of glucose values are invalid.

22. The computer-implemented method of claim 15, further comprising storing the evaluation data point as the baseline data point if no fault is detected for the evaluation data point.

23. The computer-implemented method of claim 22, further comprising comparing the evaluation data point against multiple baseline data points.