Methods for computing rolling analyte measurement values, microprocessors comprising programming to control performance of the methods, and analyte monitoring devices employing the methods

• US 7,011,630 B2
• Filed: 06/21/2002
• Issued: 03/14/2006
• Est. Priority Date: 06/22/2001
• Status: Active Grant

Abstract

The present invention relates to methods to increase the number of analyte-related signals used to provide analyte measurement values, e.g., when two or more analyte-related signals are used to obtain a single analyte measurement value a “rolling” value based on the two or more signals can be employed. In another aspect, interpolation and/or extrapolation methods are used to estimate unusable, missing or error-associated analyte-related signals. Further, interpolation and extrapolation of values are employed in another aspect of the invention that reduces the incident of failed calibrations. Further, the invention relates to methods, which employ gradients and/or predictive algorithms, to provide an alert related to analyte values exceeding predetermined thresholds. The invention includes the above-described methods, one or more microprocessors programmed to execute the methods, one or more microprocessors programmed to execute the methods and control at least one sensing and/or sampling device, and monitoring systems employing the methods described herein.

Claims

1. A method of increasing the number of analyte measurement values related to the amount or concentration of an analyte in a subject as measured using an analyte monitoring device, said method comprising

providing a series of analyte-related signals obtained from the analyte monitoring device over time, wherein (a) two or more contiguous analyte-related signals are used to obtain a single analyte measurement value (M), (b) analyte-related signals are not used to calculate more than one analyte measurement value, and (c) said two or more contiguous analyte-related signals, used to obtain the single analyte measurement value, comprise first and last analyte-related signals of the series;

mathematically computing rolling analyte measurement values, wherein (i) each rolling analyte measurement value is calculated based on two or more contiguous analyte-related signals from the series of analyte-related signals obtained from the analyte monitoring device, (ii) a subsequent rolling analyte measurement value is mathematically computed by dropping said first analyte-related signal and including an analyte-related signal contiguous and subsequent to the last analyte-related signal, (iii) further rolling analyte measurement values are obtained by repeating the dropping of the first analyte-related signal used to calculate the previous rolling analyte measurement and including an analyte-related signal contiguous and subsequent to the last analyte-related signal used to calculate the previous rolling analyte measurement, and (iv) each rolling analyte measurement value provides a measurement related to the amount or concentration of analyte in the subject; and

increasing the number of analyte measurement values derived from the analyte-related signals in the series of analyte-related signals obtained from the analyte monitoring device by serially calculating rolling analyte measurement values, thereby increasing the number of analyte measurement values relative to the number of analyte measurement values provided when two or more contiguous analyte-related signals are used to obtain a single analyte measurement value (M) and analyte-related signals are not used to calculate more than one analyte measurement value.

2. The method of claim 1, wherein said rolling analyte measurement value is an average of two or more analyte-related signals.

3. The method of claim 1, wherein said rolling analyte measurement value is a sum of two or more analyte-related signals.

4. The method of claim 1, wherein each analyte-related signal is represented by an integral over time, and said rolling analyte measurement value is obtained by integral splitting.

5. The method of claim 1, wherein said monitoring device comprises a sampling device and a sensing device, and wherein said providing the series of analyte-related signals obtained from an analyte monitoring device comprises

extracting a sample from the subject alternately into a first collection reservoir and then into a second collection reservoir using the sampling device, wherein (i) each sample comprises the analyte, and (ii) said sampling device comprises said first and second collection reservoirs;

and

sensing the analyte in each extracted sample to obtain a signal from each sample that is related to the analyte amount or concentration in the subject, thus providing a series of analyte-related signals, said sensing device comprising first and second sensors, wherein said first sensor is in operative contact with said first collection reservoir and said sensing provides signal S^A_j (where S_A is the signal from sensor A, j is the time interval), the second sensor is in operative contact with the second collection reservoir and said sensing provides signal S^B_j+1 (where S^B is the signal from sensor B, j+1 is the time interval), and an analyte measurement value is obtained using analyte-related signal from sensor A and sensor B.

6. The method of claim 5, wherein said rolling analyte measurement values are calculated as follows:

(average signal)_j=(S^B<sub>j−

1</sub>+S^A_j)/2;

 

 

Eqn. 1

(average signal)_j+1=(S^A_j+S^B_j+1)2;

 

 

Eqn. 2

(average signal)_j+2=(S^B_j+1+S^A_j+2)/2;

etc., 

 

Eqn. 3

wherein (i) (j−

1) is the measurement half-cycle previous to j, and (j+2) is two measurement half-cycles after j; and

(ii) each average signal corresponds to a rolling analyte measurement value.

7. The method of claim 5, wherein said rolling analyte measurement values are calculated as follows:

(summed signal)_j=(S^B<sub>j−

1</sub>+S^A_j);

 

 

Eqn. 4

(summed signal)_j+1=(S^A_j+S^B_j+1); and

 

 

Eqn. 5

(summed signal)_j+2=(S^B_j+1+S^A_j+2);

etc. 

 

Eqn. 6

where (j−

1) is the measurement half-cycle previous to j, and (j+2) is two measurement half-cycles after j; and

(ii) each summed signal corresponds to a rolling analyte measurement value.

8. The method of claim 1, wherein a missing or error-associated signal in the series of analyte-related signals obtained from the analyte monitoring device is estimated using interpolation before mathematically computing rolling analyte measurement values.

9. The method of claim 1, wherein a missing or error-associated signal in the series of analyte-related signals obtained from the analyte monitoring device is estimated using extrapolation before mathematically computing rolling analyte measurement values.

10. The method of claim 1, wherein said analyte is glucose.

11. The method of claim 1, wherein said analyte monitoring device comprises at least one sensing device.

12. The method of claim 1, wherein said analyte-related signal is a current or a charge related to amount or concentration of analyte in the subject.

13. The method of claim 1, wherein one or more microprocessors comprise programming to control mathematical computation of rolling analyte measurement values.

14. The method of claim 13, wherein said one or more microprocessors comprise programming to control at least one component of the analyte monitoring device.

15. The method of claim 14, wherein said analyte monitoring device comprises at least one sampling device and at least one sensing device.

16. The method of claim 15, wherein said one or more microprocessors control obtaining samples from the subject and sensing analyte concentration in each obtained sample to provide the series of analyte-related signals.

17. The method of claim 16, wherein said analyte monitoring device comprises (i) an iontophoretic sampling device, and (ii) an electrochemical sensing device.

18. The method of claim 11, wherein said sensing device comprises a biosensor device.

19. The method of claim 18, wherein said biosensor device comprises an electrode used in electrochemical detection of analyte.

20. The method of claim 11, wherein said analyte monitoring device further comprises at least one sampling device.

21. The method of claim 20, wherein said sampling device employs a sampling method selected from the group consisting of iontophoresis, sonophoresis, microdialysis, suction, and passive diffusion.

22. One or more microprocessors comprising programming to:

control mathematical computation of rolling analyte measurement values, wherein (i) each rolling analyte measurement value is calculated based on two or more contiguous analyte-related signals from a series of analyte-related signals obtained from an analyte monitoring device, (ii) said series of analyte-related signals is obtained from the analyte monitoring device over time, wherein (a) two or more contiguous analyte-related signals are used to obtain a single analyte measurement value (M), (b) analyte-related signals are not used to calculate more than one analyte measurement value, and (c) said two or more contiguous analyte-related signals, used to obtain the single analyte measurement value, comprise first and last analyte-related signals of the series, (iii) a subsequent rolling analyte measurement value is mathematically computed by dropping said first analyte-related signal and including an analyte-related signal contiguous and subsequent to the last analyte-related signal, (iv) further rolling analyte measurement values are obtained by repeating the dropping of the first analyte-related signal used to calculate the previous rolling analyte measurement and including an analyte-related signal contiguous and subsequent to the last analyte-related signal used to calculate the previous rolling analyte measurement, and (v) each rolling analyte measurement value provides a measurement related to the amount or concentration of analyte in the subject; and

increase the number of analyte measurement values derived from the analyte-related signals in the series of analyte-related signals obtained from the analyte monitoring device by serially calculating rolling analyte measurement values, thereby increasing the number of analyte measurement values relative to the number of analyte measurement values provided when two or more contiguous analyte-related signals are used to obtain a single analyte measurement value (M) and analyte-related signals are not used to calculate more than one analyte measurement value.

23. The one or more microprocessors of claim 22, wherein said analyte monitoring device comprises at least one sensing device and said one or more microprocessors are further programmed to control operation of said sensing device.

24. The one or more microprocessors of claim 23, wherein said analyte monitoring device further comprises at least one sampling device and said one or more microprocessors are further programmed to control operation of said sampling device.

25. The one or more microprocessors of claim 24, wherein said one or more microprocessors control obtaining samples from the subject and sensing analyte concentration in each obtained sample to provide the series of analyte-related signals.

26. The one or more microprocessors of claim 22, wherein said rolling analyte measurement value is an average of two or more analyte-related signals.

27. The one or more microprocessors of claim 22, wherein said rolling analyte measurement value is a sum of two or more analyte-related signals.

28. The one or more microprocessors of claim 22, wherein each analyte-related signal is represented by an integral over time, and said rolling analyte measurement value is obtained by integral splitting.

29. The one or more microprocessors of claim 22, wherein said monitoring device comprises a sampling device and a sensing device, and wherein said providing the series of analyte-related signals obtained from an analyte monitoring device comprises

extracting a sample from the subject alternately into a first collection reservoir and then into a second collection reservoir using the sampling device, wherein (i) each sample comprises the analyte, and (ii) said sampling device comprises said first and second collection reservoirs;

and

sensing the analyte in each extracted sample to obtain a signal from each sample that is related to the analyte amount or concentration in the subject, thus providing a series of analyte-related signals, said sensing device comprising first and second sensors, wherein said first sensor is in operative contact with said first collection reservoir and said sensing provides signal S^A_j (where S^A is the signal from sensor A, j is the time interval), the second sensor is in operative contact with the second collection reservoir and said sensing provides signal S^B_j+1 (where S^B is the signal from sensor B, j+1 is the time interval), and an analyte measurement value is obtained using analyte-related signal from sensor A and sensor B.

30. The one or more microprocessors of claim 29, wherein said rolling analyte measurement values are calculated as follows:

(average signal)_j=(S^B<sub>j−

1</sub>+S^A_j)/2;

 

 

Eqn. 1

(average signal)_j+1=(S^A_j+S^B_j+1)/2;

 

 

Eqn. 2

(average signal)_j+2=(S^B_j+1+S^A_j+2)/2;

etc., 

 

Eqn. 3

wherein (i) (j−

1) is the measurement half-cycle previous to j, and (j+2) is two measurement half-cycles after j, and (ii) each average signal corresponds to a rolling analyte measurement value.

31. The one or more microprocessors of claim 29, wherein said rolling analyte measurement values are calculated as follows:

(summed signal)_j=(S^B<sub>j−

1</sub>+S^A_j);

 

 

Eqn. 4

(summed signal)_j+1=(S^A_j+S^B_j+1); and

 

 

Eqn. 5

(summed signal)_j+2=(S^B_j+1+S^A_j+2);

etc. 

 

Eqn. 6

where (j−

1) is the measurement half-cycle previous to j, and (j+2) is two measurement half-cycles after j; and

(ii) each summed signal corresponds to a rolling analyte measurement value.

32. The one or more microprocessors of claim 22, wherein a missing or error-associated signal in the series of analyte-related signals obtained from the analyte monitoring device is estimated using interpolation before mathematically computing rolling analyte measurement values.

33. The one or more microprocessors of claim 22, wherein a missing or error-associated signal in the series of analyte-related signals obtained from the analyte monitoring device is estimated using extrapolation before mathematically computing rolling analyte measurement values.

34. The one or more microprocessors of claim 22, wherein said analyte is glucose.

35. The one or more microprocessors of claim 34, wherein said analyte monitoring device comprises (i) an iontophoretic sampling device, and (ii) an electrochemical sensing device.

36. The one or more microprocessors of claim 22, wherein said analyte-related signal is a current or a charge related to amount or concentration of analyte in the subject.

37. An analyte monitoring device comprising:

a sensing device; and

one or more microprocessor programmed to control operation of said sensing device, and

control mathematical computations of rolling analyte measurement values, wherein (i) each rolling analyte measurement value is calculated based on two or more contiguous analyte-related signals from a series of analyte-related signals obtained from an analyte monitoring device, (ii) said series of analyte-related signals is obtained from the analyte monitoring device over time, wherein (a) two or more contiguous analyte-related signals are used to obtain a single analyte measurement value (M), (b) analyte-related signals are not used to calculate more than one analyte measurement value, and (c) said two or more contiguous analyte-related signals, used to obtain the single analyte measurement value, comprise first and last analyte-related signals of the series, (iii) a subsequent rolling analyte measurement value is mathematically computed by dropping said first analyte-related signal and including an analyte-related signal contiguous and subsequent to the last analyte-related signal, (iv) further rolling analyte measurement values are obtained by repeating the dropping of the first analyte-related signal used to calculate the previous rolling analyte measurement and including an analyte-related signal contiguous and subsequent to the last analyte-related signal used to calculate the previous rolling analyte measurement, and (v) each rolling analyte measurement value provides a measurement related to the amount or concentration of analyte in the subject increasing the number of analyte measurement values derived from the analyte-related signals in the series of analyte-related signals obtained from the analyte monitoring device by serially calculating rolling analyte measurement values, thereby increasing the number of analyte measurement values relative to the number of analyte measurement values provided when two or more contiguous analyte-related signals are used to obtain a single analyte measurement value (M) and analyte-related signals are not used to calculate more than one analyte measurement value.

38. The analyte monitoring device of claim 37, wherein said analyte monitoring device further comprises a sampling device.

39. The analyte monitoring device of claim 38, wherein said one or more microprocessors are further programmed to control the operation of said sampling device.

40. The analyte monitoring device of claim 38, wherein said sampling device employs a sampling method selected from the group consisting of iontophoresis, sonophoresis, microdialysis, suction, and passive diffusion.

41. The analyte monitoring device of claim 39, wherein said analyte monitoring device comprises (i) an iontophoretic sampling device, and (ii) an electrochemical sensing device.

42. The analyte monitoring device of claim 37, wherein said sensing device comprise a biosensor device.

43. The analyte monitoring device of claim 42, wherein said biosensor device comprises an electrode used in electrochemical detection of analyte.