Method and apparatus for assay of electrochemical properties
First Claim
1. A method for increasing accuracy of a determination of an analyte in a sample, comprising the steps of:
- (a) applying the sample to an electrochemical test strip;
(b) applying a potential signal to the sample in the electrochemical test strip to result in a current signal that is indicative of the amount of analyte in the sample;
(c) ceasing application of the potential signal and determining a transient potential;
(d) determining from the transient potential a correction factor for the effective transport parameter (PT) or the electrode area (A) or both the effective transport parameter (PT) or the electrode area (A), and(e) applying the correction factor(s) determined in (d) to arrive at a final determination of the analyte in the sample, said final determination of the analyte in the sample being more accurate than an estimated analyte value derivable from the current signal without application of correction factor(s).
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Accused Products
Abstract
The presence of a select analyte in the sample is evaluated in an electrochemical system using a conduction cell-type apparatus. A potential or current is generated between the two electrodes of the cell sufficient to bring about oxidation or reduction of the analyte or of a mediator in an analyte-detection redox system, thereby forming a chemical potential gradient of the analyte or mediator between the two electrodes After the gradient is established, the applied potential or current is discontinued and an analyte-independent signal is obtained from the relaxation of the chemical potential gradient. The analyte-independent signal is used to correct the analyte-dependent signal obtained during application of the potential or current. This correction allows an improved measurement of analyte concentration because it corrects for device-specific and test specific factors such as transport (mobility) of analyte and/or mediator, effective electrode area, and electrode spacing (and as a result, sample volume), without need for separate calibration values. The analysis can be performed using disposable test strips in a hand held meter, for example for glucose testing.
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Citations
20 Claims
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1. A method for increasing accuracy of a determination of an analyte in a sample, comprising the steps of:
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(a) applying the sample to an electrochemical test strip; (b) applying a potential signal to the sample in the electrochemical test strip to result in a current signal that is indicative of the amount of analyte in the sample; (c) ceasing application of the potential signal and determining a transient potential; (d) determining from the transient potential a correction factor for the effective transport parameter (PT) or the electrode area (A) or both the effective transport parameter (PT) or the electrode area (A), and (e) applying the correction factor(s) determined in (d) to arrive at a final determination of the analyte in the sample, said final determination of the analyte in the sample being more accurate than an estimated analyte value derivable from the current signal without application of correction factor(s). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An apparatus for determining an analyte in a sample with increased accuracy when the apparatus is operatively connected to an electrochemical test strip specific for the analyte, said apparatus comprising:
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(a) circuitry for applying a potential signal to the sample in the electrochemical test strip to result in a current signal that is indicative of the amount of analyte in the sample; (b) circuitry for ceasing application of the potential signal and determining a transient potential; (c) circuitry for determining from the transient potential a correction factor for the effective transport parameter (PT) or the electrode area (A) or both the effective transport parameter (PT) or the electrode area (A), and (d) circuitry for applying the correction factor(s) determined in (c) to arrive at a final determination of the analyte in the sample, said final determination of the analyte in the sample being more accurate than an estimated analyte value derivable from the current signal without application of correction factor(s). - View Dependent Claims (19, 20)
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Specification