Disposable test sensor

Abstract

The present invention relates to disposable test sensors having improved sample application and measuring properties and their uses for detection, preferably, quantitative measurement, of analyte in a liquid sample like blood. In particular, the invention provides for an electrochemical biosensor which has a thin-layer fluid chamber having funnel-like shape with a novel extra wide opening as sampling entrance and a vent opening at the tip of the chamber for air escape. The thin-layer fluid chamber provides a reservoir from which a sample fluid can be drawn into it through capillary action. The extra wide sampling entrance provided by the present invention can draw blood into the chamber through any part of the opening, thus it allows easy targeting the samples with small volume, picking up smeared samples and it is more tolerant to users who jam the tip of the sensor into users' finger.

What is claimed is: 
     
         1 . An electrochemical test sensor comprising:
 a base layer having a sampling end and an electric contact end;   a middle layer formed of an electrically insulating material having a width approximately equal to a width of the base layer, and having a sampling end and an electric contact end, the middle layer forming a cutout region;   an upper layer having a sampling end and an electric contact end; and   a fluid chamber formed by the middle layer defining the cutout region, wherein the cutout region extends from the sampling end towards the electric contact end away from the sampling end;   wherein the sampling end of the middle layer is slightly recessed from a front edge of the upper layer sampling end and a front edge of the base layer sampling end, wherein the upper layer, middle layer, and base layer define two side openings in communication with the fluid chamber, a first side opening being on a first side of the sensor at the sampling end, a second side opening being on a second opposite side of the sensor at the sampling end, the two side openings being defined by the middle layer sampling end being slightly recessed from the front edge of the upper layer and base layer sampling ends;   the fluid chamber having a continuous sampling entrance defined by an open front opposite to the recessed edge of the middle layer and the two side openings;   wherein a combined length of the open front and the two side openings of the fluid chamber is less than a perimeter length of the middle layer cutout region.   
     
     
         2 . The electrochemical test sensor of  claim 1  wherein the cutout region is formed with a curving inward shape, forming a concave face. 
     
     
         3 . The electrochemical test sensor of  claim 2  wherein the curving inward shape is an arc. 
     
     
         4 . The electrochemical test sensor of  claim 1  wherein the upper layer defines a vent opening through its thickness, the vent positioned over a portion of the fluid chamber, the vent allowing gas to escape from the fluid chamber. 
     
     
         5 . The electrochemical test sensor of  claim 1  wherein the middle layer is formed of a two-sided adhesive tape. 
     
     
         6 . The electrochemical test sensor of  claim 1  wherein the upper layer further comprises a hydrophilic material on a surface facing the fluid chamber. 
     
     
         7 . The electrochemical test sensor of  claim 1  wherein the base layer further comprises electrodes, and a chemistry within the electrodes configured to cause an electrochemical signal once exposed to the fluid within the fluid chamber. 
     
     
         8 . The electrochemical test sensor of  claim 1  wherein the two side openings are configured to allow a fluid to enter the fluid chamber through one of the two side openings when the first or second side is parallel to a surface that the fluid is on. 
     
     
         9 . The electrochemical test sensor of  claim 1  wherein the cutout region is funnel shaped, having inwardly tapering sides. 
     
     
         10 . The electrochemical test sensor of  claim 1  wherein the middle layer is attached to the base layer. 
     
     
         11 . The electrochemical test sensor of  claim 1  wherein the upper layer is attached to the middle layer. 
     
     
         12 . The electrochemical test sensor of  claim 1  comprising the three layers, having the base layer directly attached to the middle layer, and the middle layer directly attached to the upper layer. 
     
     
         13 . The electrochemical test sensor of  claim 1  wherein the cutout region is defined by at least a portion of a front edge of the middle layer being recessed from the middle layer sampling end along the width of the middle layer. 
     
     
         14 . The electrochemical test sensor of  claim 1  wherein the fluid chamber is defined on a top by the upper layer, and on a bottom by the base layer. 
     
     
         15 . An electrochemical test sensor comprising:
 an electric contact end having electric contacts;   a sampling end opposite to the electric contact end comprising electrodes and a fluid chamber in communication with the electrodes;   a continuous sampling entrance to the fluid chamber comprising an open front at the sampling end, and two side openings at opposite front sides of the electrochemical test sensor at the sampling end, wherein a combined length of the open front and the two side openings is less than a perimeter length of the middle layer cutout region.   
     
     
         16 . The electrochemical test sensor of  claim 15  wherein the fluid chamber extends away from the sampling end toward the electric contact end. 
     
     
         17 . The electrochemical test sensor of  claim 1  wherein the fluid chamber is funnel shaped, having inwardly tapering sides. 
     
     
         18 . The electrochemical test sensor of  claim 15  further comprising a vent opening, the vent positioned over a portion of the fluid chamber, the vent allowing gas to escape from the fluid chamber. 
     
     
         19 . The electrochemical test sensor of  claim 15  wherein the test sensor is formed of a base layer, a middle layer, and a top layer. 
     
     
         20 . The electrochemical test sensor of  claim 19  wherein the fluid chamber is formed by a cutout region of the middle layer, and wherein the two side openings are formed by a front end of the middle layer being recessed from a front end of the base layer and a front end of the top layer.