Patent ID: 7050843

Claim:
A medical diagnostic device for measuring an analyte concentration of an electrically conductive biological fluid, comprising a multilayer structure having a first layer and a second layer sandwiching an intermediate layer, (a) the first and second layers each comprising an insulating sheet, the first layer having a first conductive surface adjoining the intermediate layer, the second layer having a first insulating surface and a second insulating surface, wherein the first insulating surface adjoins the intermediate layer, (b) the intermediate layer being an insulating layer with a cutout, having a first end and a second end, which, together with the first and second layers, defines a capillary channel to permit the sample to flow from the first end to the second end, (c) the capillary channel comprising (i) a dry reagent for reacting with the sample to yield a change in an electrical parameter that can be related to the analyte concentration of the fluid and (ii) an electrochemical cell, within which the electrical parameter is measured, (d) the conductive surface having a first insulating pattern scored into to divide the first conductive surface into it two regions, insulated from each other, wherein the insulating pattern has at least one serration, whereby sample that flows across the pattern provides a conductive path from the first end to the second end.