Test strip
First Claim
1. A disposable test strip suitable for attachment to the signal readout circuitry of a meter which performs an amperometric test to detect a current representative of the concentration of an analyte in a complex liquid medium comprising:
- (a) a working electrode which comprises an electrode pad coated with both a substance designed to engage said analyte in an oxidation-reduction reaction and a mediator compound which will transfer electrons between the oxidation-reduction reaction and the electrode pad;
(b) a dummy electrode which comprises an electrode pad which is coated with about the same amount of mediator compound as the working electrode but lacks the substance which engages the analyte in the oxidation-reduction reaction;
(c) a pseudo reference/counter electrode which comprises an electrode pad coated with a material which contains both the oxidized and reduced form of a chemical species which is designed to undergo a reduction or oxidation reaction to balance the opposite reaction at the working and dummy electrodes; and
(d) three conductive tracks, each of which extends from a contact pad adapted to interface with said readout circuitry to one of the electrode pads and which is in electrical contact with both its contact pad and its electrode pad;
wherein the electrical resistance in the circuit path from the contact pad connected to the dummy electrode through the dummy electrode is significantly greater than the electrical resistance in the circuit path from the contact pad connected to the working electrode through the working electrode.
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Accused Products
Abstract
An improved disposable test strip for use in amperometric measurement of analytes in complex liquid media, such as blood, which has three or more electrodes has been developed. This strip is designed so that different electrical potentials can be maintained between a common pseudo reference/counter electrode and each of the other electrodes upon the imposition of a common potential by an amperometric meter. This capability is imparted to the test strip by providing different circuit resistances for each of these other electrodes. The test strip can be utilized to measure a single analyte such as glucose with a background compensation via a “dummy” electrode or it can be used to measure the concentration of multiple analytes.
644 Citations
22 Claims
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1. A disposable test strip suitable for attachment to the signal readout circuitry of a meter which performs an amperometric test to detect a current representative of the concentration of an analyte in a complex liquid medium comprising:
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(a) a working electrode which comprises an electrode pad coated with both a substance designed to engage said analyte in an oxidation-reduction reaction and a mediator compound which will transfer electrons between the oxidation-reduction reaction and the electrode pad;
(b) a dummy electrode which comprises an electrode pad which is coated with about the same amount of mediator compound as the working electrode but lacks the substance which engages the analyte in the oxidation-reduction reaction;
(c) a pseudo reference/counter electrode which comprises an electrode pad coated with a material which contains both the oxidized and reduced form of a chemical species which is designed to undergo a reduction or oxidation reaction to balance the opposite reaction at the working and dummy electrodes; and
(d) three conductive tracks, each of which extends from a contact pad adapted to interface with said readout circuitry to one of the electrode pads and which is in electrical contact with both its contact pad and its electrode pad;
wherein the electrical resistance in the circuit path from the contact pad connected to the dummy electrode through the dummy electrode is significantly greater than the electrical resistance in the circuit path from the contact pad connected to the working electrode through the working electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A disposable test strip suitable for attachment to the signal readout circuitry of a meter which performs an amperometric test to detect currents representative of the concentrations of multiple analytes in a liquid medium comprising:
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(a) a first working electrode which comprises an electrode pad coated with both a substance designed to engage one of the multiple analytes in an oxidation-reduction reaction at a first electrical potential difference and a mediator compound which will transfer electrons between its oxidation-reduction reaction and its electrode pad;
(b) a second working electrode which comprises an electrode pad which is coated with both a substance designed to engage another of the multiple analytes in an oxidation-reduction reaction at a second electrical potential difference which is significantly greater than said first electrical potential difference and another mediator compound which will transfer electrons between its oxidation-reduction reaction and its electrode pad;
(c) a pseudo reference/counter electrode which comprises an electrode pad coated with a material which contains both the oxidized and reduced form of a chemical species which is designed to undergo a reduction or oxidation reaction to balance the opposite reactions at the first and second working electrodes; and
(d) three conductive tracks, each of which extends from a contact pad intended to interface with said readout circuitry to one of the electrode pads and which is in electrical contact with both its contact pad and its electrode pad;
wherein the electrical resistance in the circuit path from the contact pad connected to the first working electrode through the first working electrode is significantly greater than the electrical resistance in the circuit path from the contact pad connected to the second working electrode through the second working electrode. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification