Temperature-adjusted analyte determination for biosensor systems
View Patent ↗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.
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=c 2 *OS 2 +c 1 *OS+c 0
where A is the analyte concentration;
OS is the output signal; and
c 2 , c 1 , and c 0 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 ) =a 2 T 2 +a 1 T +a 0
where T is the sample temperature, and a 2 , a l , and a 0 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 ) =b 2 T 2 +b 1 T+b 0,
where T is the sample temperature, and b 2 , b 1 , and b 0 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=c 2 *OS 2 +c 1 *OS+c 0
where A is the analyte concentration;
OS is the output signal; and
c 2 , c 1 , and c 0 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 ) =a 2 T 2 +a 1 T+a 0
where T is the sample temperature, and a 2 , a 1 , and a 0 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 ) =b 2 T 2 +b 1 T+b 0 ,
where T is the sample temperature, and b 2 , b 1 , and b 0 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.