Temperature-adjusted analyte determination for biosensor systems

• US 8,841,133 B2
• Filed: 05/02/2013
• Issued: 09/23/2014
• 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:
  US13/875,886
• Publication Number:
  US 20130288282A1
• Time in Patent Office: 509 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, 422/400, 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;

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

selecting a previously determined correlation between output signals and analyte concentrations for a reference temperature;

selecting a previously developed normalized temperature function, the development of the normalized temperature function comprising;

determining a correlation between output signals and analyte concentrations for at least one other temperature; and

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

adjusting the previously determined correlation with the previously developed normalized temperature function, to obtain a temperature-adjusted correlation; and

calculating an analyte concentration from the output signal and the temperature-adjusted correlation.

2. The method of claim 1, where the temperature-adjusted correlation is represented as follows:

A=c₂*OS²+c₁*OS+c₀

where A is the analyte concentration;

OS is the output signal; and

c₂, c₁, and c₀ are coefficients that describe a temperature dependent weighing factor.

3. The method of claim 1, where the temperature-adjusted correlation is represented as follows:

OS_T=S_T*A_R+Int_t

where OS_T is the output signal at the sample temperature, A_R is the analyte concentration at the reference temperature, S_T is a product of a slope at the reference temperature and a normalized temperature function of the slope, and Int_t is a product of an intercept at the reference temperature and a normalized temperature function of the intercept.

4. The method of claim 3, where S_T is represented as follows:

S_T=S_R*f(T)

where T is the sample temperature, S_R is the slope of the correlation for the reference temperature, and f(T) is a temperature function that adjusts the slope for the sample temperature.

5. The method of claim 4, where f(T) is represented as follows:

f(T)=a₂T²+a₁T+a₀

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

6. The method of claim 3, where Int_T is represented as follows:

Int_T=Int_R*g(T)

where T is the sample temperature, Int_R is the intercept of the correlation for the reference temperature, and g(T) is a temperature function that adjusts the intercept for the sample temperature.

7. The method of claim 6, where g(T) is represented as follows:

g(T)=b₂T²+b₁T+b_0,

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

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

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

10. The method of claim 1, where the output signal comprises an electric signal.

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

12. 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;

where the processor;

selects a previously determined correlation between output signals and analyte concentrations for a reference temperature;

selects a previously developed normalized temperature function, the development of the normalized temperature function comprising;

determining a correlation between output signals and analyte

concentrations for at least one other temperature; and

normalizing the correlation at the at least one other temperature to the

correlation of the reference temperature;

adjusts the previously determined correlation with the previously developed normalized temperature function, to obtain a temperature-adjusted correlation adjusted to a sample temperature from the temperature sensor; and

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

13. The biosensor of claim 12, where the temperature-adjusted correlation is represented as follows:

A=c₂*OS²+c₁*OS+c₀

where A is the analyte concentration;

OS is the output signal; and

c₂, c₁, and c₀ are coefficients that describe a temperature dependent weighing factor.

14. The biosensor of claim 12, where the temperature-adjusted correlation is represented as follows:

OS_T=S_T*A_R+Int_T

where OS_T is the output signal at the sample temperature, A_R is the analyte concentration at the reference temperature, S_T is a product of a slope at the reference temperature and a normalized temperature function of the slope, and Int_T is a product of an intercept at the reference temperature and a normalized temperature function of the intercept.

15. The biosensor of claim 14, where S_T is represented as follows:

S_T=S_R*f(T)

where T is the sample temperature, S_R is the slope of the correlation for the reference temperature, and f(_T) is a temperature function that adjusts the slope for the sample temperature.

16. The biosensor of claim 15, where f(T) is represented as follows:

f(T)=a₂T²+a₁T+a₀

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

17. The biosensor of claim 14, where Int_T is represented as follows:

Int_T=Int_R*g(T)

where T is the sample temperature, Int_R is the intercept of the correlation for the reference temperature, and g(T) is a temperature function that adjusts the intercept for the sample temperature.

18. The biosensor of claim 17, where 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 normalized intercepts.

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

applying the sample to the sensor strip of the biosensor of claim 12;

determining a sample temperature;

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

adjusting a correlation between analyte concentrations and output signals at a reference temperature in response to normalized functions of slope and intercept; and

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

20. The method of claim 19, where the output signal comprises light.

21. The method of claim 19, where the output signal comprises an electrical signal.

22. The method of claim 19, where the output signal is responsive to pulsed input signals.

23. The method of claim 19, where the analyte comprises glucose and the biological fluid comprises whole blood.