Error detection in analyte measurements based on measurement of system resistance
First Claim
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1. A method for determination of an analyte in a sample comprising the steps of:
- (a) introducing the sample to an electrochemical test strip having working and counter electrodes;
(b) applying a potential difference, Vapp, between the electrodes of the test strip and observing a current signal sufficient to provide a determination of analyte in the sample and for a period of time sufficient to determine a plateau current, lplateau;
(c) switching off the applied potential at time tswitch and determining the magnitude, Vdrop, of a voltage drop arising from series electrode resistance, if present;
(d) calculating a track resistance Rtrack and comparing the determined magnitude of Rtrack against a predetermined range, and rejecting the test if the magnitude of Rtrack falls outside of the range wherein the value of Rtrack=Vdrop/Iplateau, and(e) if the magnitude is within the predetermined range, proceeding to display or communicate the result from the determination of analyte.
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Abstract
Measurement of the series track resistance of a working and counter electrode pair in an electrochemical test strip provide error detection for multiple variations in the quality of the test strip, as well as the operation of strip in the test meter. In particular, a single measurement of series resistance can be used to detect and generate an error message when an incorrect reading is likely to result due to (1) damaged electrode tracks, (2) fouled electrode surfaces, (3) dirty strip contacts, or (4) short circuit between the electrodes.
129 Citations
10 Claims
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1. A method for determination of an analyte in a sample comprising the steps of:
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(a) introducing the sample to an electrochemical test strip having working and counter electrodes; (b) applying a potential difference, Vapp, between the electrodes of the test strip and observing a current signal sufficient to provide a determination of analyte in the sample and for a period of time sufficient to determine a plateau current, lplateau; (c) switching off the applied potential at time tswitch and determining the magnitude, Vdrop, of a voltage drop arising from series electrode resistance, if present; (d) calculating a track resistance Rtrack and comparing the determined magnitude of Rtrack against a predetermined range, and rejecting the test if the magnitude of Rtrack falls outside of the range wherein the value of Rtrack=Vdrop/Iplateau, and (e) if the magnitude is within the predetermined range, proceeding to display or communicate the result from the determination of analyte. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A meter for receiving an electrochemical test strip having working and counter electrodes and providing a determination of an analyte in a sample applied to the electrochemical test strip when received in the meter, said meter comprising
(a) a housing having a slot for receiving an electrochemical test strip; -
(b) communications means for receiving input from and communicating a result to a user; and (c) means for applying a potential and to determine analyte concentration from an observed current and for measuring a plateau current, Iplateau, (d) means for switching off the potential at time tswitch and determining Vdrop; (e) means for calculating Rtrack; and (f) means for comparing Rtrack with a predetermined range and generating an error message in place of a result if Rtrack falls outside the range. - View Dependent Claims (8, 9, 10)
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Specification