Patent ID: 7550069

Claim:
A sensor strip for determining the concentration of an analyte in a sample, the sensor strip comprising: (a) a first substrate having a proximal end and an opposite distal end, the distal end being configured and arranged for insertion into a sensor reader, the first substrate defining a first side edge and a second side edge of the sensor extending from the proximal end to the distal end of the first substrate; (b) a second substrate positioned over the first substrate; (c) a spacer between the first and second substrates defining a sample chamber having only a first aperture and a second aperture, wherein the first aperture is positioned along the proximal end of the sensor and the second aperture is positioned along the first side edge of the sensor, wherein the sample chamber comprises a measurement zone having a volume of no more than 1 microliter; (d) at least one working electrode on the first substrate; and (e) at least one counter electrode on the first substrate, with a portion of the counter electrode located 25-1000 micrometers from a portion of the at least one working electrode.