Patent ID: 7285198

Claim:
An electrochemical test device for determining the presence or concentration of an analyte in an aqueous fluid sample, said electrochemical test device comprising: (a) a substrate, the substrate comprising a non-conductive material; (b) a working electrode comprising a conductive film formed with carbon nanotubes and other conductive and non conductive materials affixed to the non-conductive substrate, said working electrode having a first electrode area, a first lead and a first contact pad; (c) a counter electrode comprising a conductive film formed with carbon nanotubes and other conductive and non conductive materials affixed to the non-conductive substrate, said counter electrode having a second electrode area, a second lead and a second contact pad; (d) a reagent capable of reacting with the analyte to produce a measurable change in potential which can be correlated to the presence or concentration of the analyte in the fluid sample, said reagent overlaying at least a portion of the first electrode area of the working electrode; and (e) a reference electrode comprising a conductive coating formed with carbon nanotubes and other conductive and non conductive materials affixed to the non-conductive substrate, said reference electrode having a third electrode area, a third lead, and a third contact pad, and wherein at least a portion of the third electrode area is overlaid with a reference material.