Electrochemical analyte measurement method and system
Described and illustrated herein are systems and exemplary methods of operating an analyte measurement system having a meter and a test strip. In one embodiment, the method may be achieved by applying a first test voltage between a reference electrode and a second working electrode and applying a second test voltage between the reference electrode and a first working electrode; measuring a first test current, a second test current, a third test current and a fourth test current at the second working electrode after a blood sample containing an analyte is applied to the test strip; measuring a fifth test current at the first working electrode; estimating a hematocrit-corrected analyte concentration from the first, second, third, fourth and fifth test currents; and annunciating the hematocrit-corrected analyte concentration.
1. A method for determining a glucose concentration measurable with a system having a test strip and a meter having a test circuit including a microprocessor, the method comprising:
applying, with the test circuit, a first test voltage between a reference electrode and a second working electrode coated with a reagent layer of the test strip and applying a second test voltage between the reference electrode and a first working electrode coated with a reagent layer;
measuring a first test current, a second test current, a third test current and a fourth test current at the second working electrode after a blood sample is applied to the test strip;
measuring a fifth test current at the first working electrode;
determining, with the microprocessor, a glucose concentration based on the first, second, third, fourth and fifth test currents; and
annunciating the glucose concentration, in which the glucose concentration comprises a value obtained with an equation of the form:
G
=
[
(
I
1
I
2
)
(
a
-
b
I
3
I
4
)
xI
5
]
-
intercept
slope
where:
G is the glucose concentration;
I 1 is the first test current;
I 2 is the second test current;
I 3 is the third test current;
I 4 is the fourth test current;
I 5 is the fifth test current;
a is a first tuning parameter and b is a second tuning parameter;
intercept is an intercept value determined from a linear regression of a plot of
[
(
I
1
I
2
)
(
a
-
b
I
3
I
4
)
xI
5
]
versus a reference glucose concentration; and
slope is a slope value determined from a linear regression of a plot of
[
(
I
1
I
2
)
(
a
-
b
I
3
I
4
)
xI
5
]
versus the reference glucose concentration.
2. The method of claim 1 , in which the reference electrode, the first electrode and the second electrodes are disposed on a single plane.
3. The method of claim 1 , in which the first test current is measured from about 0.98 to about 1.00 seconds after initiation of the measuring.
4. The method of claim 1 , in which the second current is measured from about 1.98 to about 2.00 seconds after initiation of the measuring.
5. The method of claim 1 , in which the third current is measured from about 2.43 to about 2.45 seconds after initiation of the measuring.
6. The method of claim 1 , in which the fourth current is measured from about 2.61 to about 2.63 seconds after initiation of the measuring.
7. The method of claim 1 , in which the fifth current is measured from about 2.70 to about 2.72 seconds after initiation of the measuring.
8. The method of claim 1 , in which the first test current is measured from about 3.37 to about 3.39 seconds after a reaction period of time.
9. The method of claim 1 , in which the second current is measured from about 3.46 to about 3.48 seconds after a reaction period of time.
10. The method of claim 1 , in which the third current is measured from about 3.54 to about 3.56 seconds after a reaction period of time.
11. The method of claim 1 , in which the fourth current is measured from about 4.05 to about 4.07 seconds after a reaction period of time.
12. The method of claim 1 , in which the fifth current is measured from about 4.08 to about 4.10 seconds after a reaction period of time.
13. The method of claim 1 , in which first tuning parameter is from about 9.9 to about 10.2 and second tuning parameter is from about 10.8 to about 11.2.