Analyte Sensors and Methods of Making and Using the Same

• US 20150005601A1
• Filed: 09/18/2014
• Published: 01/01/2015
• Est. Priority Date: 02/26/2009
• Status: Abandoned Application

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Hoss, Udo, Thomas, Christopher Allen, McGarraugh, Geoffrey V., Hayter, Gary Alan
• Application Number:
  US14/490,519
• Publication Number:
  US 20150005601A1
• Time in Patent Office: Days
• US Class Current: 600/345
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• 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: 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: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771

Abstract

Methods and systems for providing continuous analyte monitoring including in vivo sensors that do not require any user calibration during in vivo use are provided. Also provided are methods and devices including continuous analyte monitoring systems that include in vivo sensors which do not require any system executed calibration or which do not require any factory based calibration, and which exhibit stable sensor sensitivity characteristics. Methods of manufacturing the no calibration sensors and post manufacturing packaging and storage techniques are also provided.

Claims

1. (canceled)

2. A method of processing sensor data output by a continuous analyte sensor implanted within a body, comprising:

measuring a change in sensitivity or baseline of the sensor over a time interval;

determining a drift compensation function to be applied to a plurality of time-spaced data points output by the sensor; and

applying the drift compensation function continuously to the data points.

3. The method of claim 2, wherein measuring the change in sensitivity or baseline of the sensor comprises comparing a measured sensitivity or baseline of the sensor to a predetermined sensitivity or baseline of the sensor.

4. The method of claim 3, wherein determining a drift compensation function to be applied is based, at least in part, on the predetermined sensitivity or baseline.

5. The method of claim 3, wherein a value of the predetermined sensitivity or baseline is encoded on sensor electronics.

6. The method of claim 2, further comprising comparing the measured change in sensitivity or baseline of the sensor to a priori knowledge regarding the change in sensitivity or baseline of the sensor over the time interval.

7. The method of claim 2, wherein measuring the change in sensitivity or baseline of the sensor occurs only after the sensor has been implanted within the body for at least a minimum duration.

8. The method of claim 2, further comprising prompting a user for a reference analyte value when the measured change in sensitivity or baseline of the sensor exceeds a criterion.

9. The method of claim 2, further comprising applying boundaries to the drift compensation function.

10. The method of claim 7, wherein the boundaries are based on a priori knowledge.

11. The method of claim 2, further comprising measuring an absolute sensitivity or baseline of the sensor at a time t, and wherein determining the drift compensation function to be applied to the plurality of time-spaced data points output by the sensor is based on the measured absolute sensitivity or baseline.

12. The method of claim 2, further comprising ceasing applying the drift compensation function continuously to the data points when the measured change in sensitivity or baseline of the sensor is below a threshold value.

13. The method of claim 2, further comprising ceasing applying the drift compensation function continuously to the data points after a predetermined amount of time has elapsed.

14. The method of claim 2, wherein the step of measuring a change in sensitivity or baseline of the sensor occurs over a first time interval, the step of determining a drift compensation function is based on the measured change in sensitivity or baseline of the sensor over the first time interval, and the step of applying the drift compensation function is to continuously adjust the sensor data output to compensate for changes in sensitivity or baseline of the sensor over a second time interval.

15. The method of claim 2, wherein measuring the change in sensitivity or baseline of the sensor comprises comparing a first measured sensitivity or baseline of the sensor to a second measured sensitivity or baseline of the sensor, wherein the first and second measured sensitivities or baselines of the sensor are taken at a beginning and an end, respectively, of the time interval.

16. The method of claim 15, wherein a value of the predetermined sensitivity or baseline of the sensor is assigned according to known characteristics of the body in which the sensor is implanted.

17. The method of claim 2, wherein measuring the change in sensitivity of the sensor over the time interval comprises calculating a drift rate of the sensor over the time interval.

18. The method of claim 17, wherein calculating the drift rate of the sensor comprises comparing measured analyte values to substantially time-corresponding reference analyte values.

19. The method of claim 18, wherein an expected drift rate of the sensor is calculated based on a weighted average of a current calculated drift rate and at least one previously measured drift rate.

20. A system for processing data, the system comprising:

a continuous analyte sensor configured to be implanted within a body; and

sensor electronics configured to receive and process sensor data output by the sensor, the sensor electronics including a processor configured to measure a change in sensitivity or baseline of the sensor over an interval of time;

determine a drift compensation function to be applied to a plurality of time-spaced data points output by the sensor over a next interval of time; and

apply the drift compensation function continuously to the data points over the next interval of time.

21. The system of claim 20, wherein measuring the change in sensitivity or baseline of the sensor comprises comparing a first measured sensitivity or baseline of the sensor to a second measured sensitivity or baseline of the sensor, wherein the first and second measured sensitivities or baselines of the sensor are taken at a beginning and an end, respectively, of the time interval.

22. The system of claim 20, wherein the processor is further configured to compare a measured sensitivity or baseline of the sensor to a predetermined sensitivity or baseline of the sensor.

23. The system of claim 22, wherein determining a drift compensation function to be applied is based, at least in part, on the predetermined sensitivity or baseline.

24. The system of claim 22, wherein a value of the predetermined sensitivity or baseline is encoded on sensor electronics.

25. The system of claim 22, wherein a value of the predetermined sensitivity or baseline of the sensor is assigned according to known characteristics of the body in which the sensor is implanted.

26. The system of claim 20, wherein the processor is further configured to compare the measured change in sensitivity or baseline of the sensor to a priori knowledge regarding the change in sensitivity or baseline of the sensor over the time interval.

27. The system of claim 20, wherein measuring the change in sensitivity of the sensor over the time interval comprises calculating a drift rate of the sensor over the time interval.

28. The system of claim 27, wherein calculating the drift rate of the sensor comprises comparing measured analyte values to substantially time-corresponding reference analyte values.

29. The system of claim 27, wherein an expected drift rate of the sensor is calculated based on a weighted average of a current calculated drift rate and at least one previously measured drift rate.

30. The system of claim 20, wherein measuring the change in sensitivity or baseline of the sensor occurs only after the sensor has been implanted within the body for at least a minimum duration.

31. The system of claim 20, wherein the processor is further configured to prompt a user for a reference analyte value when the measured change in sensitivity or baseline of the sensor exceeds a criteria.

32. The system of claim 20, wherein the processor is further configured to store the change in sensitivity or baseline of the sensor for later use.

33. The system of claim 20, wherein the applied drift compensation function is a stepwise function.

34. The system of claim 20, wherein the applied drift compensation function functions to apply a mathematical inverse of a mathematical equation that describes the change in sensitivity or baseline of the sensor over the time interval.

35. The system of claim 20, wherein the processor is further configured to apply boundaries to the drift compensation function.

36. The system of claim 35, wherein the boundaries are based on a priori knowledge.

37. The system of claim 20, wherein the processor is further configured to measure an absolute sensitivity or baseline of the sensor at a time t, and wherein determining the drift compensation function to be applied to the plurality of time-spaced data points output by the sensor is based on the measured absolute sensitivity or baseline.

38. The system of claim 20, wherein the processor is further configured to cease applying the drift compensation function continuously to the data points when the measured change in sensitivity or baseline of the sensor is below a threshold value.

39. The system of claim 20, wherein the processor is further configured to cease applying the drift compensation function continuously to the data points after a predetermined amount of time has elapsed.

40. The system of claim 20, wherein the processor is configured to determine a drift compensation function based on the measured change in sensitivity or baseline of the sensor over the interval of time, and to apply the drift compensation function continuously to the data points over the next interval of time to continuously adjust the sensor data output to compensate for changes in sensitivity or baseline of the sensor over a second time interval.