Method and apparatus for rapid electrochemical analysis
First Claim
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1. A method for determining an analyte concentration in a physiological sample, the method comprising the steps of:
- (a) introducing the physiological sample into an electrochemical cell comprising;
(i) first and second electrodes in a spaced apart relationship; and
(ii) a reagent layer comprising an enzyme and a mediator;
(b) detecting the presence of sample in said electrochemical cell;
(c) applying a first electric potential having a first polarity to the electrochemical cell and measuring cell current as a function of time to obtain a first time-current transient immediately after said detecting step;
(d) applying a second electric potential having a second polarity to the cell, wherein the second polarity is opposite the first polarity, and measuring cell current as a function of time to obtain a second time-current transient; and
(e) calculating a first current value from the second time-current transient;
(f) calculating a second current value from the second time-current transient and a third current value from the first time-current transient;
(g) calculating a ratio which comprises the second current value divided by the third current value; and
(h) multiplying the first current value less a background value by the ratio to derive analyte concentration wherein steps (c) through (h) occur in less than about 10 seconds from an occurrence of step (b).
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Abstract
Methods and apparatus for electrochemically determining an analyte concentration value in a physiological sample are disclosed. The methods include using a test strip in which two time-current transients are measured by a meter electrically connected to an electrochemical test strip. Integrative current values are derived from the time-current transients and used in the calculation of analyte concentration.
28 Citations
32 Claims
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1. A method for determining an analyte concentration in a physiological sample, the method comprising the steps of:
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(a) introducing the physiological sample into an electrochemical cell comprising; (i) first and second electrodes in a spaced apart relationship; and (ii) a reagent layer comprising an enzyme and a mediator; (b) detecting the presence of sample in said electrochemical cell; (c) applying a first electric potential having a first polarity to the electrochemical cell and measuring cell current as a function of time to obtain a first time-current transient immediately after said detecting step; (d) applying a second electric potential having a second polarity to the cell, wherein the second polarity is opposite the first polarity, and measuring cell current as a function of time to obtain a second time-current transient; and (e) calculating a first current value from the second time-current transient; (f) calculating a second current value from the second time-current transient and a third current value from the first time-current transient; (g) calculating a ratio which comprises the second current value divided by the third current value; and (h) multiplying the first current value less a background value by the ratio to derive analyte concentration wherein steps (c) through (h) occur in less than about 10 seconds from an occurrence of step (b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for determining an analyte concentration in a physiological sample, the method comprising:
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(a) introducing the physiological sample into an electrochemical cell comprising; (i) first and second electrodes in a spaced apart relationship; and (ii) a reagent layer comprising an enzyme and a mediator; (b) detecting the presence of sample in said electrochemical cell; (c) applying a first electric potential having a first polarity to the cell and measuring cell current as a function of time to obtain a first time-current transient immediately after said detecting step; (d) applying a second electric potential having a second polarity to the cell, wherein the second polarity is opposite the first polarity, and measuring cell current as a function of time to obtain a second time-current transient; and (e) calculating a first integrative current value from the first time-current transient and a second integrative current value from the second time-current transient; (f) calculating a ratio which comprises the second value divided by the first current value; (g) calculating a correction factor that comprises the ratio; (h) calculating an initial concentration value from the first and/or second time-current transients; and (i) multiplying the initial concentration value less a background value by the correction factor to derive the analyte concentration wherein steps (c) through (i) occur in less than about 10 seconds from an occurrence of step (b). - View Dependent Claims (28, 29, 30, 31)
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32. A method for determining an analyte concentration in a physiological sample, the method comprising:
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(a) introducing the physiological sample into an electrochemical cell comprising; (i) first and second electrodes in a spaced apart relationship; and (ii) a reagent layer comprising an enzyme and a mediator; (b) detecting the presence of sample in said electrochemical cell; (c) applying a first electric potential having a first polarity to the electrochemical cell and measuring cell charge as a function of time to obtain a first time-charge transient immediately after said introducing step; (d) applying a second electric potential having a second polarity to the cell, wherein the second polarity is opposite the first polarity, and measuring cell charge as a function of time to obtain a second time-charge transient; (e) calculating a first charge value from the second time-charge transient; (f) calculating a second charge value from the second time-charge transient and a third charge value from the first time-charge transient; (g) calculating a ratio based on the second charge value and the third charge value; and (h) multiplying the first charge value less a background value by the ratio to derive analyte concentration wherein steps (c) through (h) occur in less than about 10 seconds from an occurrence of step (b).
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Specification