Patent ID: 6461496
Filing Date: 2002-10-08
Classification: C12Q,G01N,Y10T

Abstract:
An electrochemical sensor strip for determining the concentration of glucose in blood or interstitial fluid, the sensor strip comprising:(a) a first inert, non-conducting polymeric base layer and a second inert, non-conducting polymeric base layer, each layer having a side length and a shorter end length; (b) a spacer material positioned between and connecting the first and second base layers, the spacer material shaped to define a channel between the layers, the spacer defining: (i) a first opening at a first end of the sensor strip; (ii) a second opening at a first side edge of the sensor strip; and (iii) a sample chamber adjacent the first opening; (c) an electrode pair comprising a first working electrode and a counter electrode, each formed on one of the base layers and exposed to the sample chamber, at least a portion of the first working electrode being within 200 &mgr;m of a portion of the counter electrode; (d) a measurement zone adjacent the first working electrode and counter electrode within the sample chamber, the measurement zone sized to contain a volume of no more than 1 &mgr;L of sample; (e) redox mediator disposed in the sample chamber; (f) an indicator electrode that is a second working electrode formed on the same base layer as the first working electrode and the counter electrode, the indicator electrode: (i) exposed to the sample chamber; and (ii) positioned farther along the channel from the first opening than the first working electrode; and (g) a conductive trace extending from each of the electrodes along a length of the base layer and extending to a position adjacent a second end length of the sensor strip.