System and methods for providing corrected analyte concentration measurements
First Claim
1. A biosensor for measuring a constituent concentration in blood, said biosensor comprising:
- a sample reception region for receiving a blood sample; and
a reaction reagent system comprising;
an oxidation-reduction enzyme specific for the constituent;
a first electron mediator capable of being reversibly reduced and oxidized such that a first electrochemical signal resulting from the reduction or oxidation is related to the constituent concentration in the blood sample;
a second electron mediator capable of undergoing an electrochemical redox reaction where a second electrochemical signal produced by oxidation or reduction of the second mediator is not directly related to the constituent concentration in the blood sample; and
wherein the second electrochemical signal changes based on the hematocrit level of the blood sample.
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Abstract
Methods and devices for determining the concentration of a constituent in a physiological sample are provided. The physiological sample is introduced into an electrochemical cell having a working and counter electrode. At least one electrochemical signal is measured based on a reaction taking place at the cell. The preliminary concentration of the constituent is then calculated from the electrochemical signal. This preliminary concentration is then multiplied by a hematocrit correction factor to obtain the constituent concentration in the sample, where the hematocrit correction factor is a function of the at least one electrochemical signal. The subject methods and devices are suited for use in the determination of a wide variety of analytes in a wide variety of samples, and are particularly suited for the determination of analytes in whole blood or derivatives thereof, where an analyte of particular interest is glucose.
73 Citations
44 Claims
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1. A biosensor for measuring a constituent concentration in blood, said biosensor comprising:
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a sample reception region for receiving a blood sample; and
a reaction reagent system comprising;
an oxidation-reduction enzyme specific for the constituent;
a first electron mediator capable of being reversibly reduced and oxidized such that a first electrochemical signal resulting from the reduction or oxidation is related to the constituent concentration in the blood sample;
a second electron mediator capable of undergoing an electrochemical redox reaction where a second electrochemical signal produced by oxidation or reduction of the second mediator is not directly related to the constituent concentration in the blood sample; and
wherein the second electrochemical signal changes based on the hematocrit level of the blood sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for determining a constituent concentration in blood, the method comprising:
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(a) introducing the blood sample into an electrochemical cell comprising;
(i) spaced apart working and counter electrodes; and
(ii) a redox reagent system comprising an enzyme;
a first electron mediator capable of being reversibly reduced and oxidized such that a first electrochemical signal resulting from the reduction or oxidation is related to the constituent concentration in the blood sample; and
a second electron mediator capable of capable of undergoing an electrochemical redox reaction where a second electrochemical signal produced by oxidation or reduction of the second mediator is not directly related to the constituent concentration in the blood sample and changes based on the hematocrit level of the blood sample;
(b) obtaining the first electrochemical signal;
(c) obtaining the second electrochemical signal;
(d) determining an initial value corresponding to the constituent concentration of the sample using data from the first electrochemical signal; and
(e) correcting the initial value corresponding to the constituent concentration of the sample to remove an effect of the hematocrit level of the sample using a statistical correlation algorithm and data from the second electrochemical signal. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for determining the hematocrit corrected concentration of an analyte in a physiological sample, said method comprising:
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(a) introducing the physiological sample into an electrochemical cell comprising;
(i) spaced apart working and counter electrodes; and
(ii) a redox reagent system comprising an enzyme and a mediator;
(b) applying a first electric potential to the reaction cell and measuring cell current during a first 50 milliseconds of the first electric potential as a function of time to obtain a first time-current transient;
(c) applying a second electric potential to said cell, and measuring cell current as a function of time to obtain a second time-current transient;
(d) deriving a preliminary analyte concentration from said first and second time-current transients; and
(e) multiplying the preliminary analyte concentration by a hematocrit correction factor based on the first and second time-current transient to derive the hematocrit corrected analyte concentration in said sample;
whereby the hematocrit corrected concentration of said analyte in said sample is determined. - View Dependent Claims (31, 32, 33, 34, 35)
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36. A method of manufacturing a plurality of test strips, comprising:
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forming a web containing a conductive layer and a base layer;
partially forming said plurality of test strips by electrically isolating a first group of conductive components in the conductive layer using a first process;
subsequently forming said plurality of test strips by electrically isolating a second group of conductive components in the conductive layer using a second process wherein first and second processes are not the same; and
forming a reagent layer including;
an enzyme;
a first electron mediator capable of being reversibly reduced and oxidized such that a first electrochemical signal resulting from the reduction or oxidation is related to the constituent concentration in the blood sample; and
a second electron mediator capable of undergoing an electrochemical redox reaction where a second electrochemical signal produced by oxidation or reduction of the second mediator is not directly related to the constituent concentration in the blood sample and changes based on the hematocrit level of the blood sample. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44)
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Specification