Temperature-adjusted analyte determination for biosensor system

• US 7,781,222 B2
• Filed: 08/07/2008
• Issued: 08/24/2010
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Wu, Huan-Ping, Nelson, Christine D.
• Primary Examiner(s): WALLENHORST, MAUREEN
• Application Number:
  US12/187,743
• Publication Number:
  US 20090023222A1
• Time in Patent Office: 747 Days
• Field of Search: 436/8, 436/14, 436/63, 436/95, 436/147, 436/149, 436/150, 436/164, 422/55, 422/68.1, 422/82.01, 422/82.02, 422/82.05, 422/82.09, 422/82.12, 73/10.1, 73/10.2, 435/14, 708/205
• US Class Current: 436/147
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: G01N 27/26 by investigating electrochemical variables; by using electrolysis or electrophoresis
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: G16B 40/10 Signal processing, e.g. from mass spectrometry [MS] or from PCR
• CPC Class Codes: G16B 99/00 Subject matter not provided for in other groups of this subclass
• CPC Class Codes: Y10T 436/10 Composition for standardization, calibration, simulation, stabilization, preparation or preservation; processes of use in preparation for chemical testing
• CPC Class Codes: Y10T 436/104998 Glucose, ketone, nitrate standard or control
• CPC Class Codes: Y10T 436/12 Condition responsive control
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

A biosensor system determines analyte concentration from an output signal generated by an oxidation/reduction reaction of the analyte. The biosensor system adjusts a correlation for determining analyte concentrations from output signals at one temperature to determining analyte concentrations from output signals at other temperatures. The temperature-adjusted correlation between analyte concentrations and output signals at a reference temperature may be used to determine analyte concentrations from output signals at a sample temperature.

Claims

1. A method for determining an analyte concentration in a sample of a biological fluid, comprising:

determining a sample temperature in a sample of biological fluid;

generating an output signal in response to a redox reaction of an analyte in the sample;

adjusting a correlation between analyte concentrations and output signals at a reference temperature in response to the sample temperature,

the correlation comprising a slope and an intercept,

where the adjusting the correlation comprises adjusting the slope in response to a normalized temperature function of the slope, and adjusting the intercept in response to a normalized temperature function of the intercept; and

determining the analyte concentration in the sample from the temperature-adjusted correlation and the output signal.

2. The method of claim 1, where the temperature-adjusted correlation between analyte concentrations in a biological fluid and output signals is represented as follows:

3. The method of claim 2, where the normalized temperature function for slope comprises a regression analysis of normalized slopes.

4. The method of claim 3, where the normalized temperature function for slope, f(T), is represented as follows:

ƒ

(T)=a₂T²+a₁T+a₀,

where T is the sample temperature and a₂, a₁, and a₀ are coefficients of a regression analysis representing the normalized slopes.

5. The method of claim 2, where the normalized temperature function for intercept comprises a regression analysis of normalized intercepts.

6. The method of claim 5, where the normalized temperature function for intercept, g(T) is represented as follows:

g(T)=b₂T²+b₁T+b₀,

where T is the sample temperature and b₂, b₁, and b₀ are coefficients of a regression analysis representing the normalized intercepts.

7. The method of claim 1, further comprising generating the output signal in response to an electrochemical process.

8. The method of claim 1, where the output signal comprises light.

9. The method of claim 1, where the output signal comprises an electrical signal.

10. The method of claim 1, further comprising generating the output signal in response to pulsed input signals.

11. The method of claim 1, where the analyte comprises glucose and the biological fluid comprises whole blood.

12. A method for adjusting a correlation between analyte concentrations and output signals at a reference temperature in response to temperature, comprising:

determining the correlation between analyte concentrations and output signals for a reference temperature, the correlation of the reference temperature comprising a slope and an intercept;

determining a correlation between analyte concentrations and output signals at least one other temperature, the correlation at the at least one other temperature comprising a slope and an intercept;

developing normalized temperature functions of slope and intercept for the correlation of the reference temperature, the developing comprising;

normalizing the slope of the correlation at the at least one other temperature to the slope of the correlation of the reference temperature, and

normalizing the intercept of the correlation at the at least one other temperature to the intercept of the correlation of the reference temperature; and

adjusting the slope and the intercept of the correlation of the reference temperature in response to the normalized temperature functions of slope and intercept.

13. The method of claim 12, where the normalized temperature function of slope comprises a regression analysis of normalized slopes.

14. The method of claim 13, where the normalized temperature function of slope, f(T), is represented as follows:

ƒ

(T)=a₂T²+a₁T+a₀,

where T is the at least one other temperature and a₂, a₁, and a₀ are coefficients of a regression analysis representing the normalized slopes.

15. The method of claim 12, where the normalized temperature function for intercept comprises a regression analysis of normalized intercepts.

16. The method of claim 15, where the normalized temperature function for intercept, g(T) is represented as follows:

g(T)=b₂T²+b₁T+b₀,

where T is the at least one other temperature and b₂, b₁, and b₀ are coefficients of a regression analysis representing the normalized intercepts.

17. The method of claim 12, where the correlation between analyte concentrations and output signals for a reference temperature is represented as follows:

18. The method of claim 12, where the temperature-adjusted correlation of a reference temperature is represented as follows:

19. The method of claim 12, where the output signals comprise light.

20. The method of claim 12, where the output signals comprise an electrical signal.

21. The method of claim 12, further comprising generating the output signals in response to pulsed input signals.

22. The method of claim 12, where the analyte comprises glucose and the biological fluid comprises whole blood.

23. A biosensor for determining an analyte concentration in a biological fluid, comprising:

a measuring device having a processor connected to a sensor interface and a temperature sensor;

a sensor strip having a sample interface on a base, where the sample interface is adjacent to a reservoir formed by the base; and

where the processor adjusts a correlation between analyte concentrations and output signals at a reference temperature, where the correlation comprises a slope and an intercept,

where the adjustment is in response to a normalized temperature function of the slope, a normalized temperature function of the intercept, and a sample temperature from the temperature sensor, and

where the processor determines an analyte concentration from the temperature-adjusted correlation in response to an output signal from the sample interface.

24. The biosensor of claim 23 where the temperature-adjusted correlation of a reference temperature is represented as follows:

25. The biosensor of claim 24, where the normalized temperature function for slope, f(T), comprises a regression analysis of normalized slopes and is represented as follows:

ƒ

(T)=a₂T²+a₁T+a₀,

where T is the sample temperature and a₂, a₁, and a₀ are coefficients of a regression analysis representing the normalized slopes.

26. The biosensor of claim 24, where the normalized temperature function for intercept, g(T), comprises a regression analysis of normalized intercepts and is represented as follows:

g(T)=b₂T²+b₁T+b_o,

where T is the sample temperature and b₂, b₁, and b₀ are coefficients of a regression analysis representing the normalized intercepts.

27. The biosensor of claim 23, where the output signal comprises light.

28. The biosensor of claim 23, where the output signal comprises an electrical signal.

29. The biosensor of claim 23, where the output signal is responsive to pulsed input signals.

30. The biosensor of claim 23, where the analyte comprises glucose and the biological fluid comprises whole blood.