Patent Publication Number: US-2015068893-A1

Title: Biosensor test strip for biosensor test device

Description:
This application claims the benefit under 35 U.S.C. §119(c) of U.S. Provisional Application No. 61/877,217, filed on Sep. 12, 2013, entitled “BIOSENSOR TEST STRIP FOR BIOSENSOR MONITOR”, the disclosure of which is incorporated by reference herein. 
    
    
     FIELD 
     The present disclosure relates to a biosensor test strip and the detection or measurement of analytes in body fluid samples. 
     BACKGROUND 
     For patients suffering from high blood glucose, a biosensor monitor, such as a blood glucose meter, is necessary for routine daily self-checks. When using a conventional biosensor monitor, a user normally inserts a single-use biosensor test strip into the biosensor monitor and introduces body fluid sample, such as blood, to the test strip. The reaction zone of a test strip is normally coated with reagent (i.e., glucose oxidase or GOD), which covers parts of a working electrode and a reference electrode. The body fluid samples interact with the reagent and provide the biosensor an electric signal. After the signal is interpreted as a result of the electrochemical reaction of reagents with analytes in the body fluid sample, the single-use test strip is discarded. 
     For example, as shown in  FIG. 1 , the test strip  10  comprises a base layer  11 , a working electrode  12 , a reference electrode  13 , a reaction zone  15 , tracks( 14   a ,  14   b ) and contact pads (not shown in  FIG. 1 ). Typically, reagents are deposited or coated on a reaction zone  15 , and this reaction zone covers parts of the working electrode  12  and the reference electrode  13 . The reagent reacts with a biological sample in a way that an analyte of interest in the biological sample can be detected and measured when an electrical potential is applied between the electrodes  12  and  13 . The measured electrical property of the reacted sample may therefore indicate a biochemical property, such as the blood glucose level, of the sample. 
     Theoretically, the same biological samples should result in the same readings if the samples are tested by test strips made in the same batch. However, due to various manufacturing conditions, each of the fabricated biosensor test strips may be different in some aspects. For example, some electrochemical characteristics of the enzyme reagents are highly susceptible to manufacturing and environmental variables. These variables may negatively affect, for example, the number and sizes of the air bubbles present in the enzyme reagent and hence the homogeneous distribution of the enzyme and mediator, such as potassium ferricyanide. Another inevitable manufacturing variable is the shifting of the position of coating area during manufacturing process. That is, though the position of the coating area of a reagent is predetermined, it is difficult to fabricate two biosensor test strips with exactly the same reaction zone at the same position and covering the same area of the electrodes. This could lead to substantial measurement error because the ratio of overlapping area a1 (the overlapping area between the reaction zone  15  and the working electrode  12 ) to a2 (the overlapping area between the reaction zone  15  and the reference electrode  13 ) is different. These variables thus constitute inherent differences of test strips. Another aspect of the conventional test strip is that each test strip is capable of performing only one test. In addition, the electrodes are all formed on a single layer which would limit the possibility of different designs of the electrodes and the contact pads. Still another aspect of the conventional test strip is that the electrical potential reduces when the reaction between a biological sample and reagents occurs. This would lead to a longer testing period and inaccurate results. 
     What is needed, therefore, is a solution to overcome the above described disadvantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a schematic plan view of a typical biosensor test strip for use in measuring a concentration of an analyte of interest in a biological sample in related arts. 
         FIG. 2  is a schematic plan view of an embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 3  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 4  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5A  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5B  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5C  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5D  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5E  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5F  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5G  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5H  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5I  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5J  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5K  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 5L  is a schematic plan view of another embodiment of a biosensor test strip according to the present disclosure. 
         FIG. 6  is a schematic plan view of another embodiment of a biosensor test strip with multiple tests according to the present disclosure. 
         FIG. 7  is a schematic plan view of another embodiment of a biosensor test strip with multiple tests according to the present disclosure. 
         FIG. 8  is a schematic plan view of another embodiment of a biosensor test strip with multiple tests according to the present disclosure. 
         FIG. 9  is a schematic plan view of another embodiment of a biosensor test strip with multiple tests according to the present disclosure. 
         FIG. 10  is a schematic plan view of another embodiment of a biosensor test strip with multiple tests according to the present disclosure. 
         FIG. 11A  is a schematic plan view of the structure of another embodiment of a biosensor test strip with multiple tests which has only one base layer according to the present disclosure. 
         FIG. 11B  is a schematic plan view of the structure of another embodiment of a biosensor test strip with multiple tests which has two base layers according to the present disclosure. 
         FIGS. 12A and 12B  are schematic plan views of the structure of another embodiment of a biosensor test strip with multiple tests which has two base layers according to the present disclosure. 
         FIGS. 13A and 13B  are schematic plan views of the structure of another embodiment of a biosensor test strip with multiple tests which has two base layers according to the present disclosure. 
         FIGS. 14A and 14B  are schematic plan views of the structure of another embodiment biosensor test strip with multiple tests which has two base layers according to the present disclosure. 
         FIGS. 15A and 15B  are schematic plan views of the structure of another embodiment of a biosensor test strip with multiple tests which has two base layers according to the present disclosure. 
         FIGS. 16A and 16B  are schematic plan views of the structure of another embodiment of a biosensor test strip with multiple tests which has two base layers according to the present disclosure. 
         FIGS. 17A and 17B  are schematic plan views of the structure of another embodiment of a biosensor test strip with multiple tests which has two base layers according to the present disclosure. 
         FIGS. 18A and 18B  are schematic plan views of the structure of the connection between the biosensor monitor connector terminal and the contact pads of the biosensor test strip according to the present disclosure. 
         FIGS. 19A ,  19 B and  19 C illustrate the different ways of inserting a biosensor test strip in to a biosensor monitor according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In order to enhance an understanding of the principles of the disclosure, several embodiments of a biosensor test strip and their use in a biosensor monitor will now be described in detail below and with reference to the drawings. It is to be noted that no limitation of the scope of the disclosure is intended. Alterations and modifications in the illustrated device, and further applications of the principles of the disclosure as illustrated therein, as would normally occur to a person having ordinary skill in the art to which the disclosure relates, are contemplated, and desired to be protected. 
     Referring to  FIGS. 2-5 , a biosensor test strip  20  in accordance with embodiments is provided. The biosensor test strip  20  comprises, at least, a first electrode  22 , a second electrode  23 , a first track  24   a , a second track  24   b , a first contact pad, a second contact pad (contact pads are not shown) and a reaction zone  25  formed on a base layer  21 . The first track  24   a  is electrically connected to both the first electrode  22  and the first contact pad. The second track  24   b  is electrically connected to both the second electrode  23  and the second contact pad. The reaction zone  25  may be fully or partially coated with reagents so long as to directly contact parts of the first electrode  22  and the second electrode  23 . 
     Referring specifically to  FIG. 2 , in this embodiment, the second electrode  23  comprises two electrode pads  23   a  and  23   b , and the first electrode  22  is formed and located between the two electrode pads  23   a  and  23   b , i.e., the second electrode  23  partially surrounds the first electrode  22 . A defined quantity of a reagent is partially or fully coated on the reaction zone  25  and covers parts of the first electrode  22  and the second electrode  23 . The overlapping area or contacting area between the reaction zone  25  and the first electrode  22  is designated as A 22  while the overlapping areas between the reaction zone  25  and the electrode pads  23   a  and  23   b  are A 23   a  and A 23   b  respectively. E1 is the edge of an electrode that is located closest to a sample introducing port  26  while E2 is the edge of another electrode that is the farthest to the sample introducing port  26 . The electrodes closest and farthest to the sample introducing port are subject to change. To illustrate, as indicated in  FIG. 2 , E1 is the edge of electrode pad  23   a  that is closest to the sample introducing port  26  and E2 is the edge of the electrode pad  23   b  that is farthest to the sample introducing port  26 . As long as the reaction zone  25  is located within the edges E1 and E2, the area ratio of A 23   a  plus A 23   b  to A 22  will always be the same and thus allow a certain range of position shift of the reaction zone and ultimately reduce errors when measuring the analyte of interest in a biological sample. To further illustrate, if the reaction zone  25  is shifted and coated on a position closer to the sample introducing port  26  during manufacturing process, the area of A 23   a  will enlarge and A 23   b  will shrink. However the sum of the area of A 23   a  and A 23   b  will still be the same and thus the area ratio of A 23   a  plus A 23   b  to A 22  will stay the same, which would lead to a more consistent measurement of a biological sample. 
     Another aspect of the present disclosure concerns  FIG. 3 . In one embodiment, the second electrode  23  comprises only one electrode pad  23   a . A third electrode  27 , which is electrically independent to the first electrode  22  and the second electrode  23 , is employed to contact the reaction zone  25 . An overlapping area or contacting area between the reaction zone  25  and the third electrode  27  is designated as A 27 . The biosensor monitor would provide an electrical potential between the first electrode  22  and the second electrode  23  to measure the response. Once the biological sample reacts with the reagents on the reaction zone  25 , the first electrode  22  and the second electrode  23  will be electrically connected and the biosensor monitor will sense a drop in the measured electrical property value (i.e., voltage, current or resistance) through the first electrode  22  and the second electrode  23 . The drop in the electrical property will increase with the completion of the reaction. However, the drop in the electrical property would slow down the testing process, affect the final reading of the biological sample and thus would provide an inaccurate value to the user. By employing the third electrode  27  which provides a predetermined potential to the reaction zone  25 , the third electrode  27  would stabilize the measurement, speed up the process of reading and increase the accuracy of the reading. 
     Referring also to  FIG. 4 , which is another embodiment of the present disclosure, the second electrode  23  comprises two electrode pads  23   a  and  23   b , and both the first electrode  22  and the third electrode  27  are formed in an area between the electrode pads  23   a  and  23   b . In this embodiment, the electrodes described in  FIGS. 2 and 3  are employed. The electrode pads  23   a  and  23   b  of the second electrode  23  are used to keep the ratio of A 23   a  plus A 23   b  to A 22  fixed. The third electrode  27  is employed to provide a stable measuring potential to the biosensor test strip and the biological sample. Therefore, by using both the fixed ratio provided by the second electrode  23  and the stabilization of measurement provided by the third electrode  27 , the biosensor test strip and the biosensor monitor together would provide a faster, a more stable and a more accurate reading to a user. 
       FIG. 5A  is another embodiment of the present disclosure. As illustrated, the electrode pad  23   a  and  23   b  are formed in an open circular shape where the opening allows the first electrode  22  and the third electrode  27  to be deployed between the electrodes  23   a  and  23   b . The first and the third electrodes  22 ,  27  are also formed in a semicircle shape to correspond to the second electrode  23 . The first and second electrodes may be deployed as described in  FIGS. 5B-5L . Specifically,  FIGS. 5B ,  5 C,  5 F and  5 K illustrated that the first electrode  2121  is composed of two electrode pads (not annotated) and the second electrode  2122  is positioned between the two electrode pads of the first electrode  2121 . In  FIG. 5K , the first electrodes  2121  and the second electrode  2122  each may have more than one electrode pads (not annotated) and form a comb-like electrode structure. One or more electrode pads of the first electrode  2121  may be positioned between two electrode pads of the second electrodes  2122 . Similarly, one or more electrode pads of the second electrode  2122  may be positioned between two electrode pads of the first electrode  2121 . It is to be noted that the outermost electrode pads of the first electrode  2121  and/or the second electrode  2122  may not be positioned between any electrode pads since it is the outermost electrode pad. In  FIGS. 5D and 5E , the first electrode  2121  and the second electrode  2122  may be made in a substantially circular shape. Specifically, the first electrode  2121  may substantially surround the second electrode  2122  while the arrangement leaves the two electrodes  2121  and  2122  electrically independent. As illustrated in  FIG. 5E , the first electrode  2121  have a semi-circular shape and part of the second electrode  2122  is between the electrode pads of first electrode  2121  or is partly surrounded by the first electrode  2121 . 
     In  FIGS. 5G-5J , and  5 L, a third electrode  2123  is adopted. As illustrated in  FIG. 5G , the second electrode  2122  and the third electrode  2123  is positioned between the electrode pads of the first electrode  2121  while the arrangement leaves the first, second and third electrodes ( 2121 ,  2122 ,  2123 ) electrically independent. In  FIGS. 5H and 5J , the first electrode  2121 , the second electrode  2122  and the third electrode  2123  are in a substantially square or rectangular shape. The first electrode  2121  and the second electrode  2122  may each substantially surround half of the third electrode pad  2123  while leave the third electrode  2123  electrically independent. As illustrated in  5 H and  5 J, the third electrode  2123  is an enlarged rectangular electrode pad and is substantially surrounded by the first electrode  2121  and the second electrode  2122  while the arrangement leaves the three electrodes electrically independent. In FIG. SI, the first electrode  2121 , the second electrode  2122  and the third electrode  2123  are made in a substantially circular shape. As illustrated in FIG. SI, the third electrode  2123  is an enlarged circular electrode pad and is substantially surrounded by the first electrode  2121  and the third electrode  2122  while the arrangement leaves the three electrodes electrically independent. Also, as described in  FIG. 5L , a third electrode  2123  is employed to have several electrode pads which form a comb-like electrode structure. One or more electrode pads of the third electrode  2123  may be positioned between the electrode pads of the first electrode  2121 , or between the electrode pads of the second electrodes  2122 , or between the electrode pad of the first electrode  2121  and the electrode pad of the second electrode  2122 . 
     It is to be noted that the present disclosure may include other sort of electrodes. Referring to  FIG. 6 , a sub-first electrode  6221  that is electrically coupled to a first electrode  622  is located at a position closest to a sample introducing port  626 . Likewise, a sub-second electrode  6231  that is electrically coupled to a second electrode  623  is located at a position farthest to the sample introducing port  626 . Once the biological sample is introduced to the sample introducing port and passes to the sub-first  6221  and sub-second electrodes  6231 , the biosensor monitor will sense signals through the sub-first  6221  and sub-second  6231  electrodes and multiple parameters such as the time period of the signal started and ended, the current, the voltage, the resistance and so on are measured and recorded. Such information is useful to identify specific information such as sample fluid velocity and useful to provide users with supplement information to interpret the results of the test. Still in another embodiment, a fill-detect electrode  629  that provides information of whether the sample is sufficient may be employed as well. The fill-detect electrode  629  is set at any position where it is can determine if there is enough biological sample to perform a complete test. In this embodiment, the fill-detect electrode  629  is formed at the position farthest to the sample introducing port. A first check node  6220  is electrically connected to the first electrode  622  and the second check node  6230  is electrically connected to the second electrode  623 . By measuring the impedance or the resistance of the reagent between the first check node  6220  and the second check node  6230 , the biosensor test strip  620  with incorrect reagent impedance or resistance is considered to be defective. One skilled in the art would appreciate that the above mentioned tracks, electrodes, nodes and contact pads may be deployed in any other way which may provide the same result as described above. A single biosensor test strip  620  includes at least eight sets of sample test sections  631 . Pre-cuts  630  are formed on the base layer  621  and, by pressuring the pre-cut  630 , each section  631  can be obtained and can perform one test. On each section lies at least the first electrode  622 , the sub-first electrode  6221 , the second electrode  623 , the sub-second electrode  6231 , the fill-detect electrode  629 , a first track  6222 , a second track  6232 , a first contact pad  6223 , a second contact pad  6233 , the first check node  6220 , the second check node  6230  and the fill-detect contact pad  6293 . The first track  6222  is formed thereon the base layer  621  and direct an electrical signal to the first contact pad  6223 . The second track  6232  is formed thereon the base layer  621  and direct an electrical signal to the second contact pad  6233 . While the first electrode  622 , the first check node  6220 , the sub-first electrode  6221 , the first track  6222  and the first contact pad  6223  are in electrical connection and form a first circuit, the second electrode  623 , the second check node  6230 , the sub-second electrode  6231 , the second track  6232  and the second contact pad  6233  are in electrical connection and form a second circuit. The fill-detect  629  and the fill-detect contact pad  6293  are in electrical connection. The first circuit, the second circuit and the fill-detect circuit are electrically independent on each section while not in use. Parts of the first contact pad  6223  and the second contact pad  6233  are substantially parallel to the longitudinal side of the base layer  621 , while the first electrode  622 , the sub-first electrode  6221 , the second electrode  623 , the sub-second electrode  6231  and the fill-detect electrode  629  are substantially perpendicular to the longitudinal side of the base layer  621 . It is to be noted that the sub-first, the sub-second, the fill-detect electrodes and the first and second nodes can be optional and may be employed or left out if desired. In practical uses, the biosensor test strip  620  is first inserted into the test strip inserting port (not shown) of the biosensor monitor. The sample test section  631  is broken off by pressuring the pre-cut  630 , leaving the sample test section  631  protruding out of the test strip inserting port of the biosensor monitor and being ready for the application of a biological sample. 
     In another embodiment not shown in figures, the fill-detect electrode is formed at the position between sub-second electrode and the second electrode. As will be appreciated by the person skilled in the art, the fill-detect electrode can be integrated into the sub-first or sub-second electrode such that no fill-detect electrode is needed to provide a fill-detect function. 
     Referring to  FIG. 7 , the tracks, the electrodes, and the contact pads are deployed in a similar pattern as described in  FIG. 3 . Specifically, in this embodiment, a third electrode  724  is employed. Pre-cuts  630  are formed on the base layer  621  and, by pressuring the pre-cut  630 , each section  631  can be obtained and can perform one test. The third electrode  724  is disposed between the first electrode  622  and the sub-second electrode. Parts of the first contact pad  6223  and the second contact pad  6233  are substantially parallel to the longitudinal side of the base layer  621 , while parts of the first electrode  622 , the sub-first electrode  6221 , the second electrode  623 , the sub-second electrode  6231 , the third electrode  627  and the fill-detect electrode  629  are substantially perpendicular to the longitudinal side of the base layer  621 . It is to be noted that the sub-first, the sub-second, the fill-detect electrodes and the first and second nodes can be optional and may be employed or left out if desired. 
     Referring now to  FIG. 8 , the tracks, the electrodes, and the contact pads are deployed in a similar pattern as described in  FIG. 2 . Pre-cuts  830  are formed on the base layer  821  and, by pressuring the pre-cut  830 , each section  831  can be obtained and can perform one test. On each section  831  lies at least the first electrode  822 , the sub-first electrode  8221 , the second electrode  823 , the sub-second electrode  8231 , the fill-detect electrode  829 , a first track  8222 , a second track  8232 , a first contact pad  8223 , a second contact pad  8233 , the first check node  8220 , the second check node  8230  and the fill-detect contact pad  8293 . Parts of the first contact pad  8223  and the second contact pad  8233  are substantially perpendicular to the longitudinal side of a biosensor test strip  820 , while parts of the first electrode  822 , the sub-first electrode  8221 , the second electrode  823 , the sub-second electrode  8231  and the fill-detect electrode  829  are substantially parallel to the longitudinal side of the biosensor test strip  820 . It is to be noted that the sub-first, the sub-second, the fill-detect electrodes and the first and second nodes are an option and may be employed or left out if desired. 
     Referring to  FIG. 9 , the tracks, the electrodes, and the contact pads are deployed in a similar pattern as described in  FIG. 3 . Pre-cuts  830  are formed on the base layer  821  and, by pressuring the pre-cut  830 , each section  831  can be obtained and can perform one test. On each section  831  lies at least the first electrode  822 , the sub-first electrode  8221 , the second electrode  823 , the sub-second electrode  8231 , the fill-detect electrode  829 , a first track  8222 , a second track  8232 , a first contact pad  8223 , a second contact pad  8233 , the first check node  8220 , the second check node  8230  and the fill-detect contact pad  8293 . A third electrode  924  is further employed in this embodiment. The third electrode  924  is disposed between the first electrode  822  and the fill-detect electrode  829 . Parts of the first contact pad  8223  and the second contact pad  8233  are substantially perpendicular to the longitudinal side of a biosensor test strip  820 , while parts of the first electrode  822 , the sub-first electrode  8221 , the second electrode  823 , the sub-second electrode  8231 , the third electrode  924  and the fill-detect electrode  829  are substantially parallel to the longitudinal side of the biosensor test strip  820 . It is to be noted that the sub-first, the sub-second, the fill-detect electrodes and the first and second nodes are optional and may be employed or left out if desired. 
     Referring to  FIG. 10 , the tracks and the electrodes are deployed in a similar pattern as described in  FIG. 1 . Pre-cuts  1030  are formed on the base layer  1021  and, by pressuring the pre-cut  1030 , each section  1031  can be obtained and can perform one test. On each section  1031  lies at least the first electrode  1022 , the sub-first electrode  1022   a , the second electrode  1023 , the sub-second electrode  1023   s , the fill-detect electrode  1029 , a first track  1022   t , a second track  1023   t , a first contact pad  1022   c , a second contact pad  1023   c , the first check node  1022   n , the second check node  1023   n  and the fill-detect contact pad  1029   c . The first contact pad  1022   c , the second contact pad  1023   c , the first electrode  1022 , the sub-first electrode  1022   s , the second electrode  1023 , the sub-second electrode  1023   s  and the fill-detect electrode  1029  are all substantially parallel to the longitudinal side of the biosensor test strip  1020 . It is to be noted that the sub-first, the sub-second, the fill-detect electrodes and the first and second nodes are optional and may be employed or left out if desired. 
     Another embodiment of the present disclosure is shown in  FIG. 11A . A biosensor test strip with multiple tests comprises a base layer  1111  and an electrical circuit deployed as described in  FIGS. 6-10  on the base layer  1111 . In this embodiment, the biosensor test strip comprises an electric circuit, an insulating layer  1112 , an adhesive layer  1113  and a cover layer  1114 . The insulating layer  1112  is formed on the base layer  1111  and exposes part of contact pads  1115  comprising a first contact pad  1153 , a second contact pad  1151  and a fill-detect contact pad  1152 , electrodes  1116  comprising a first electrode  1162 , a sub-first electrode  1163 , a second electrode  1161  and a sub-second electrode  1164 , reaction zones  1118  and check nodes  1117  comprising a first check node  1172  and the second check node  1171 . The insulating layer  1112  further comprises a slot  1121 , a reaction zone opening  1124  and a venting slot  1123 . The insulating layer  1112  is in fluidic communication with external air and the reaction zone opening  1124 . The reaction zone opening  1124  is also in fluidic communication with the venting slot  1123 . The adhesive layer  1113  is formed on the insulating layer  1112  and exposes part of contact pads  1115 , electrodes  1116 , reaction zones  1118  and check nodes  1117 . The cover layer  1114  is formed on the adhesive layer  1113  and exposes part of the contact pads  1115 . Upon assembling of the biosensor test strip, a channel is defined by all layers presented in  FIG. 11A  and thus provides a path for a biological sample to enter to the reaction zone  1118  to react with a reagent and for the air to leave through the venting slot  1123 . It is to be noted that embodiments described here shall not limit the scope of the disclosure. In an alternative embodiment, the venting slot  1123  can be deployed in a different way to have more than one venting slots and thus have more than two holes to vent the air. 
     Another embodiment of the present disclosure is shown in  FIG. 11B . A biosensor test strip with multiple tests comprises a first layer  1221  and a second layer  1212 , and two sets of electric circuits, each deployed on one base layer. The biosensor test strip further comprises an insulating layer  1112   b , and an adhesive layer  1113   b . As shown in  FIG. 11B , the biosensor test strip for multiple tests comprises a first base layer  1221  where a first electrode  1222 , a first track  1225 , a sub-first electrode  1223  and a first contact pad  1224  are formed thereon. Pre-cuts  1226  are so formed on both the first base layer  1221  and the second base layer  1211  that when the pre-cuts  1226  are broken it produces a blunt and same edge on both the first base layer  1221  and the second base layer  1211 . A first opening area  1227  is formed on the first base layer  1221  and defined by the first base layer  1221 . The biosensor test strip for multiple tests further comprises a second base layer  1211  where a second electrode  1212 , a second track  1215 , a sub-second electrode  1213  and a second contact pad  1214  are formed thereon. A fill-detect electrode  1228  and fill-detect contact pad  1229  are also formed on the first base layer  1221 . A second opening area  1217  is formed on the second layer  1211  and defined by the second base layer  1211 . The first opening area  1227  exposes the second contact pad  1214  for electrically connecting to the biosensor monitor and the second opening area  1217  exposes the first contact pad  1224  as well. An insulating layer  1112   b  and an adhesive layer  1113   b  are formed between the first base layer  1221  and the second base layer  1211 . The adhesive layer  1113   b  directly contacts the first base layer  1221  or directly contacts the second base layer  1211 . That is, the position of the adhesive layer  1113   b  and the insulating layer  1112   b  between the two base layers  1211  and  1221  are exchangeable. A first electrical circuit comprises the first contact pad  1224 , the first electrode  1222 , the sub-first electrode  1223 , and the first track  1225 . A second electrical circuit described here comprises the second contact pad  1214 , the second electrode  1212 , the sub-second electrode  1213  and the second track  1215 . The insulating layer  1112   b  exposes part of the contact pads ( 1224 ,  1214 ,  1229 ), part of electrodes ( 1222 ,  1223 ,  1212 ,  1213 ,  1228 ), and part of the reaction zones of both electrical circuits deployed on two base layers  1211  and  1221 . In an assembled biosensor test strip, the sides bearing the electrical circuits will face each other with the contact pads ( 1224 ,  1214 ,  1229 ) exposed for electrically connecting to a biosensor monitor (not shown). From a top view of the assembled biosensor strip, the first electrode  1222  will not overlap with the second electrode  1212 . It is to be noted that the sub-first, the sub-second, the fill-detect electrodes and the check nodes are optional and may be employed or left out if desired. 
     Another embodiment of the present disclosure is shown in  FIGS. 12A and 12B . The overall biosensor test strip structure is similar to that described in  FIG. 11B . Some differences are described here. A first electrode  1312  and a second electrode  1322  are enlarged and, from the top view of the assembled biosensor test strip, the first electrode  1312  overlaps with the second electrode  1322 . Even though a small amount of biological sample reacts with just a small part of the reagent on the reagent zone, both the first electrode  1312  and the second electrode  1322  will be in direct contact with the mixed samples of the reagent and the biological samples. In contrast, the embodiment given in  FIG. 11B  will have only one electrode (which would be the first electrode  1222 ) in direct contact with the reacted biological sample when a small amount of biological sample is introduced. A first electrode  1312 , a first track  1315 , a sub-first electrode  1313 , a first contact pad  1314  and a pre-cuts  1316  are formed on a first base layer  1311 . A first opening area  1317  is formed on the first base layer  1311  and defined by the first base layer  1311 . A second electrode  1322 , a sub-second electrode  1323  and a second contact pad  1324  are formed on a second base layer  1321 . Pre-cuts  1326  are formed on a second base layer  1321  at a position corresponding to the pre-cuts  1316  on a first base layer  1311 . In this embodiment, the contact pads ( 1314 ,  1324 ) are substantially parallel to the longitudinal side of the biosensor test strip, while the electrodes ( 1312 ,  1313 ,  1322 ,  1323 ) are substantially perpendicular to the longitudinal side of the biosensor test strip. 
     Referring now to  FIGS. 13A and 13B , the electrical circuit is similar to what is described in  FIG. 2 . In this embodiment, a first contact pad  1414 , a second contact pads  1424  and a fill-detect contact pad  1430  are substantially perpendicular to the longitudinal side of the biosensor test strip, while a first electrode  1412 , a sub-first electrode  1413 , a second electrode  1422 , a sub-second electrode  1423  and a fill-detect electrode  1431  are substantially parallel to the longitudinal side of the biosensor test strip. 
     Referring to  FIGS. 14A and 14B , the electrical circuit is similar to that described in  FIG. 8 . In this embodiment, a first contact pad  1514 , a second contact pad  1524 , a third contact pad  1541  and a fill-detect contact pad  1530  are substantially perpendicular to the longitudinal side of the biosensor test strip, while a first electrode  1512 , a second electrode  1522 , a third electrode  1540  and a fill-detect electrode  1531  are substantially parallel to the longitudinal side of the biosensor test strip. 
     Referring to  FIGS. 15A and 15B , the electrical circuit is similar to that described in  FIGS. 12A and 12B . In this embodiment, a first electrode  1612  and a second electrode  1622  are enlarged. A first contact pad  1614 , a second contact pads  1624  and a fill-detect contact pad  1630  are substantially perpendicular to the longitudinal side of the biosensor test strip, while a first electrode  1612 , a sub-first electrode  1613 , a second electrode  1622 , a sub-second electrode  1623  and a fill-detect electrode  1631  are substantially parallel to the longitudinal side of the biosensor test strip. 
     Referring to  FIGS. 16A and 16B , the electrical circuit is similar to that described in  FIG. 10 . In this embodiment, a first electrode  1712 , a first contact pad  1714 , a fill-detect electrode  1731 , a fill-detect contact pad  1730 , a second electrode  1722  and a second contact pad  1724  are substantially parallel to the longitudinal side of the biosensor test strip. 
     Referring to  FIGS. 17A and 17B , the electrical circuit is similar to that described in  FIGS. 12A and 12B . In this embodiment, a first electrode  1812  and a second electrode  1822  are enlarged. A first electrode  1812 , the first contact pad  1814 , a fill-detect electrode  1831 , a fill-detect contact pad  1830 , a second electrode  1822  and a second contact pad  1824  are substantially parallel to the longitudinal side of the biosensor test strip. 
     It is to be noted that the deployment of the electrodes and the electrode pads described in  FIG. 6  to  FIG. 17B  may be arranged as described in, but not limited to, the embodiments of  FIGS. 5A-5L . 
     Referring to  FIGS. 18A and 18B , a biosensor test device includes the biosensor monitor and the single biosensor test strip, the connection between the biosensor monitor and the single biosensor test strip with multiple tests is illustrated. As indicated, a biosensor test strip comprises two base layers  192  and  193 , and at least two contact pads  191  and  190 . The contact pad  191  is formed on the base layer  192  while the contact pad  190  is formed on the base layer  193 . The contact pad  191  is electrically connected to a biosensor monitor connector terminal  194  and the contact pad  190  is electrically connected to a biosensor monitor connector terminal  195 . As indicated in  FIG. 19A , the axis of the terminals  194  and  195  are parallel to the contact pads  191  and  190  while in  FIG. 19B  the axis of the terminals are perpendicular to the contact pads. To further clarify the deployment of the terminals, the terminal  194  contacts the contact pad  191  on one side of the biosensor test strip while terminal  195  contacts the contact pad  190  on the opposite side of the biosensor test strip.  FIGS. 18A and 18B  describe embodiments that apply to all embodiments given in  FIGS. 11-17 . 
     Another aspect of the present disclosure is illustrated in  FIGS. 19A ,  19 B and  19 C. A biosensor test strip  202  with multiple tests can be inserted in to the biosensor monitor in different directions at different places. As indicated in  FIG. 19A , a biosensor monitor has a test strip inserting port  201  located on a non-corner area. The biosensor test strip  202  with multiple tests is inserted into the biosensor monitor in a direction A, where the shorter side of the biosensor test strip  202  will contact the biosensor monitor first. Further, the sample introducing port (not annotated) which is either located on the longitudinal side or the shorter side of the biosensor test strip  202 , is exposed for a user to introduce biological samples.  FIGS. 6 ,  7 ,  11 B and  12  could be performed in the way described here where the sample introducing port is located on the short side of the biosensor test strip  202 . 
     Referring to  FIG. 19B , a biosensor monitor has a test strip inserting port  201  located on a corner area. The biosensor test strip  202  with multiple tests is inserted into the biosensor monitor in a direction B, where the longitudinal side of the biosensor test strip  202  will contact the biosensor monitor first. Further, the sample introducing port, which is either on the longitudinal side or the short side of the test strip, is exposed for a user to introduce biological samples.  FIGS. 8 ,  9 , and  13 ,  14  and  15  could be performed in the way described here. 
     Referring to  FIG. 19C , a biosensor monitor has a test strip inserting port  201  located on a corner area. The biosensor test strip  202  with multiple tests is inserted into the biosensor monitor in a direction C, where the shorter side of the biosensor test strip  202  will contact the biosensor monitor first. Further, the sample introducing port, which is either on the longitudinal side or the short side of the test strip, is exposed for a user to introduce biological samples.  FIGS. 10 ,  16  and  17  could be performed in the way described here where the sample introducing port is located on the longitudinal side of the biosensor test strip  202 . 
     It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in details, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.