Patent ID: 6540891
Filing Date: 2003-04-01
Classification: C12Q

Abstract:
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.