GB2509166A

GB2509166A - Analytical test strip with reagent diffusion bridge

Info

Publication number: GB2509166A
Application number: GB201223325A
Authority: GB
Inventors: John Crawford; James RODGERS
Original assignee: Cilag GmbH International
Current assignee: Cilag GmbH International
Priority date: 2012-12-21
Filing date: 2012-12-21
Publication date: 2014-06-25
Anticipated expiration: 2032-12-21
Also published as: GB2509166B; GB201223325D0; HK1198716A1

Abstract

An electrochemical analytical test strip 100 for the determination of an analyte (such as glucose) in, or a characteristic (e.g., hematocrit) of, a bodily fluid sample includes an electrically-insulating base layer 110, a capillary sample-receiving chamber 170, a working electrode 124 on the base layer in the chamber, a reagent layer 130 on the base layer in the chamber and overlapping the working electrode, a counter electrode 122 devoid of the reagent layer on the base layer in the chamber and a reagent diffusion bridge 150. The reagent diffusion bridge is of predetermined dimensions and adjoins the counter electrode 122 and the reagent layer 130, thereby defining a predetermined separation distance therebetween. The working and counter electrodes are disposed on the base layer in a coplanar configuration. The magnitude and timing of an electrochemical response is measured and used to determine the analyte.

Description

ANALYTICAL TEST STRIP

WITH CO-PLANAR ELECTRODES

AND A REAGENT DIFFUSION BRIDGE

FIELD OF THE INVENTION

[0001] The present invention relates, in general, to medical devices and, in particular, to analytical test strips and related methods.

BACKGROUND OF THE INVENTION

[0002] The determination (e.g., detection and/or concentration measurement) of an analyte in a fluid sample and/or the determination of a characteristic of a fluid sample (such as hematocrit) are of particular interest in the medical field. For example, it can be desirable to determine glucose, ketone bodies, cholesterol, lipoproteins, triglycerides, acetaminophen and/or HbAlc concentrations in a sample of a bodily fluid such as urine, blood, plasma or interstitial fluid. Such determinations can be achieved using analytical test strips, based on, for example, visual, photometric or electrochemical techniques. Conventional electrochemical-based analytical test strips are described in, for example, U.S. Patent Nos. 5,708,247, and 6,284,125, each of which is hereby incorporated in full by reference.

SUMMARY OF THE INVENTION

[0003] In a first aspect, there is provided an electrochemical-based analytical test strip for the determination of at least one of an analyte in, and a characteristic of, a bodily fluid sample, the electrochemical-based analytical test strip comprising: an electrically-insulating base layer; a capillary sample-receiving chamber; a working electrode disposed on the electrically-insulating base layer in the capillary sample-receiving chamber; a reagent layer disposed on the electrically-insulating base layer in the capillary sample-receiving chamber and overlapping the working electrode; a counter electrode devoid of the reagent layer and disposed on the electrically-insulating base layer in the sample receiving chamber; a reagent diffusion bridge of predetermined dimensions disposed in the capillary sample-receiving chamber, the reagent diffusion bridge adjoining the counter electrode and the reagent layer and defining a predetermined separation distance therebetween; wherein the working electrode and counter electrode are disposed on the electrically-insulating base layer in a co-planar configuration.

[0004] The electrochemical-based analytical test strip may further include: a patterned conductor layer disposed over the electrically-insulating base layer, the patterned conductive layer including the counter electrode and working electrode; a patterned insulation layer that includes the reagent diffusion bridge; a top layer, and wherein at least the electrically-insulating substrate layer, patterned conductor layer, patterned insulation layer, and top layer define the capillary sample-receiving chamber.

[0005] The reagent diffusion bridge may have a width in the range of 5Oum to 200uni. The reagent diffusion bridge may have a thickness in the range of 30 nanometers to 200 microns. The reagent diffusion bridge may be a mediator diffusion bridge. The bodily fluid sample may be a whole blood sample. The analyte may be glucose. The top layer may include a capillary sample-receiving chamber-defining groove. The counter electrode may be entirely devoid of reagents. The reagent diffusion bridge may overlap the reagent layer between the counter electrode and the working electrode.

[0006] In a second aspect, a method for determining at least one of an analyte in a bodily fluid sample, comprises: applying a bodily fluid sample to a capillary sample-receiving chamber of an electrochemical-based analytical test strip, the capillary sample-receiving chamber having disposed therein: a working electrode of the electrochemical-based analytical test strip; a reagent layerof the electrochemical-based analytical test strip overlapping the working electrode; a counter electrode of the electrochemical-based analytical test strip, the counter electrode being devoid of the reagent layer and disposed in a co-planar configuration with the working electrode; and a reagent diffusion bridge of predetermined dimensions of the electrochemical-based analytical test strip adjoining the counter electrode and the reagent layer and defining a predetermined separation distance therebetween; and measuring magnitude and timing of at least a first electrochemical response of the electrochemical-based analytical test strip; and determining the analyte based on the magnitude and timing of the first measured electrochemical response.

[0007] The bodily fluid sample may be a whole blood sample. The analyte may be glucose. The first electrochemical response may be an amperometric response. The measuring of the amperometric response may include the measuring of current peak magnitude and current peak timing of the amperometric response. The determining step may comprise determining a hematocrit-corrected analyte concentration. The reagent layer may be an enzymatic reagent layer containing a mediator and timing of the response is dependent on diffusion of the mediator across the reagent diffusion bridge. The determination step may employ a 2-factor interaction algorithm to determine the analyte. The determination may employ a polynomial equation to determine the analyte. The reagent diffusion bridge may have a width in the range of 5Oum to 200um and a thickness in the range of 30 nanometers to 200 microns.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention, in which: FIG. 1 is a simplified exploded perspective view of an electrochemical-based analytical test strip according to an embodiment of the present invention; FIG. 2 is a simplified, exploded, end view of the electrochemical-based analytical test strip of FIG. 1; FIG. 3 is a simplified top view of the electrochemical-based analytical test strip of FIG. 1; FIG. 4 is a simplified, partially-transparent perspective view of the electrochemical-based analytical test strip of FIG. 1; FIG. 5 is a simplified end view of a portion of the electrochemical-based analytical test strip of FIG. 1; and FIG. 6 is a flow diagram depicting stages in a method for determining an analyte in a bodily fluid sample according to an embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0009] The following detailed description should be read with reference to the drawings, in which like elements in different drawings are identically numbered.

The drawings, which are not necessarily to scale, depict exemplary embodiments for the purpose of explanation only and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

[0010] As used herein, the terms about or "approximately" for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein.

[0011] In general, electrochemical-based analytical test strips for the determination of at least one of an analyte in, and a characteristic of, a bodily fluid sample according to embodiments of the present invention include an electrically-insulating base layer, a capillary sample-receiving chamber, a working electrode disposed on the electrically-insulating base layer in the capillary sample-receiving chamber, a reagent layer disposed on the electrically-insulating base layer in the capillary sample-receiving chamber and overlapping the working electrode, and a counter electrode devoid of the reagent layer and disposed on the electrically-insulating base layer in the sample receiving chamber. The electrochemical-based analytical test strips also include a reagent diffusion bridge of predetermined dimensions disposed in the capillary sample-receiving chamber. In addition, the reagent diffusion bridge adjoins the counter electrode and the reagent layer and defines a predetermined separation distance therebetween. Moreover, the working electrode and counter electrode are disposed on the electrically-insulating base layer in a co-planar configuration.

[0012] As used herein, the terms "adjoins" and "adjoining" refer to elements that abut one another, are adjacent to one another, and/or border one another and includes elements wherein one of the elements (e.g., a reagent layer) at least partially overlaps another element (for example, a working electrode).

[0013] Electrochemical-based analytical test strips according to embodiments of the present invention are beneficial in that they are, for example, easily and inexpensively manufactured and highly accurate due to the defined separation of the reagent layer and a counter electrode that is devoid of reagent. Also, since the reagent diffusion bridge precisely defines the diffusion distance from the reagent layer to the counter electrode, the timing and magnitude of an electrical response (e.g., the timing and magnitude of a peak current) can be employed to determine not only an analyte in the bodily fluid sample but also characteristics of the bodily fluid sample (such as hematocrit) that affect diffusion within the bodily fluid sample.

[0014] It should be noted that in electrochemical-based analytical test strips according to the present invention, the reagent layer contacts only the working electrode and not the counter electrode. Therefore, the development of an electrochemical response (such as an amperometric response) is fully reagent diffusion dependent. Thus, the electrochemical response contains diffusion-dependent signal characteristics that can be measured and used to correct an analyte determination based on, for example, hematocrit and/or temperature of the bodily fluid sample. The presence of a reagent diffusion bridge of predetermined dimensions (which separates the reagent layer and counter electrode along the entire length of the capillary sample-receiving chamber and is operatively insoluble) provides for a consistent, well-defined, minimum diffusion path (distance) and thus an accurate determination.

[0015] In addition, the reagent diffusion bridge can overlap the reagent layer and/or counter electrode layer, thus accounting for any imperfections in the alignment of the reagent layer and counter electrode.

[0016] FIG. 1 is a simplified exploded perspective view of an electrochemical-based analytical test strip 100 according to an embodiment of the present invention. FIG. 2 is a simplified, exploded end view of electrochemical-based analytical test strip 100. FIG. 3 is a simplified top view of electrochemical-based analytical test strip 100. FIG. 4 is a simplified, partially-transparent perspective view of electrochem ical-based analytical test strip 100. FIG. 5 is a simplified end view of a portion of electrochemical-based analytical test strip 100.

[0017] Referring to FIGs. 1-5, electrochemical-based analytical test strip 100 for the determination of an analyte (such as glucose) in a bodily fluid sample (for example, a whole blood sample) includes an electrically-insulating base layer 110, a patterned conductor layer 120 (such as a patterned conductive carbon layer), a reagent layer 130, a patterned insulation layer 140 that includes a reagent diffusion bridge 150, and a top layer 160. Patterned conductor layer 120 includes a counter electrode 122 and a working electrode 124 (see FIG. 5 in particular).

[0018] The disposition and alignment of electrically-insulating base layer 110, patterned conductor layer 120 (which includes counter electrode 122 and working electrode 124), reagent layer 130, patterned insulation layer 140 (and reagent diffusion bridge 150 thereof), and top layer 160 are such that capillary sample-receiving chamber 170 is defined within electrochemical-based analytical test strip 100. The definition of such a capillary sample-receiving chamber is in part due to groove 180 in top layer 160 (see FIGs. 2).

[0019] It should be noted that in the embodiment depicted in FIGs. 1-5, reagent diffusion bridge 150 extends the entire length of capillary sample-receiving chamber 170 (see FIG. 4 in particular).

[0020] Referring to FIGs. 2 and 3 in particular, exemplary but non-binding dimensions for electrochemical-based analytical test strip 100 include an overall width "A" of 6mm, an overall length "B" of 6mm, a dimension "C" of patterned conductor layer 120 of 2.6mm, a gap width "D" in the patterned conductor layer of 0.6mm, a width "E" of reagent layer 130 of 0.60mm, A width "F" of groove 180 of 0.8mm and an overall width "G" of top layer 160 of 2.5mm. Additional exemplary but non-binding dimensions are a depth of 0.10mm for groove 180, a thickness of 0.01mm for patterned insulation layer 140.

[0021] In general, reagent diffusion bridges included in electrochemical-based analytical test strips according to embodiments of the present invention can have any suitable dimensions bearing in mind that the height and width dimensions of the reagent diffusion bridge determine the minimum diffusion path length of a electrochemical reaction rate-limiting reagent (typically a mediator) crossing the reagent diffusion bridge. Typical but non-limiting reagent diffusion bridge widths are in the range of 50 microns to 200 microns and heights in the range of 30 nanometers to 200 microns.

[0022] In addition, although reagent diffusion bridge 150 is depicted as having generally rectangular cross-section above the upper surfaces of counter electrode 122 and enzymatic reagent layer 130 (see the detail and perspective of FIG. 5), reagent diffusion bridges included in embodiments of the present invention can have any suitable cross-sectional shape including, for example, a trapezoidal, wedge, curved or triangular cross-sectional shape. Moreover, in the embodiment of FIGs. 1 through 5, the reagent diffusion bridge is depicted as being much wider than it is high (i.e., the width is much greater than the height).

In this configuration, the shortest diffusion path length for a reagent (e.g., a mediator) is approximately the width of the reagent diffusion bridge between the counter electrode and the reagent layer, although a more accurate shortest diffusion path length would be approximately twice the height of the reagent diffusion bridge plus the width of the reagent diffusion bridge.

[0023] Since the time required for an electrochemical response to be achieved will vary linearly with the square root of the mean free path diffusion length, the dimensions of the reagent diffusion bridge are also factor in the time required to determine an analyte (i.e., the "test time"). For example, a mean free path diffusion length of 150 microns is expected to result in a test time in the range of 3 seconds to 15 seconds for the determination of glucose in a whole blood sample using conventional reagents known to one of skill in the art. Similarly, a mean free path diffusion length of 300 microns would be expected to result in a test time of approximately 30 seconds to 1 minute and a mean free path diffusion length of 500 microns a test time of approximately 3 minutes.

[0024] During use, a bodily fluid sample is applied to electrochemical-based analytical test strip 100 and fills the capillary sample-receiving chamber, thereby, operatively contacting counter electrode 122 (which is devoid of reagent) and working electrode 124 disposed in the capillary sample-receiving chamber.

[0025] Electrically-insulating base layer 110 can be any suitable electrically-insulating substrate layer known to one skilled in the art including, for example, a nylon substrate, polycarbonate substrate, a polyimide substrate, a polyvinyl chloride substrate, a polyethylene substrate, a polypropylene substrate, a glycolated polyester (PETG) substrate, or a polyester substrate.

The electrically-insulating substrate layer can have any suitable dimensions including, the aforementioned width and length of 6mm.

[0026] Electrically-insulating base layer 110 provides structure to the strip for ease of handling and also serves as a base for the application (e.g., printing or deposition) of subsequent layers (e.g., a patterned conductor layer and patterned insulation layer). It should be noted that patterned conductor layers employed in analytical test strips according to embodiments of the present invention can take any suitable shape and be formed of any suitable materials including, for example, metal materials and conductive carbon materials.

[0027] Patterned conductor layer 120 can be formed of any suitable conductive material including, for example, gold, palladium, platinum, indium, titanium-palladium alloys and electrically conducting carbon-based materials including carbon inks. Examples of carbon inks include DuPont 7240W and DuPont BQ226 carbon inks. Typical carbon inks include, for example, carbon Black, graphite, and optionally other metal flake pigments, e.g., platinum, gold, and palladium, and a suitable binder. Suitable binders include, for example, vinyl resins (including vinyl chloride polymers and copolymers, epoxy resins, epoxy novolac resins, polyester resins, and acrylic resins, polyurethane resins, epoxy-acrylates, polyesters acrylates, and polyesters urethane acrylates.

Suitable carbon inks may also contain water or suitable solvents for ease of coating that will evaporate after printing to leave a dry film. Examples of suitable solvents include aliphatic and/or aromatic hydrocarbons, ketonic solvents, alcohols, ethers, glycol ethers, esters (e.g., dibasic esters) or chlorinated solvents.

[0028] Reagent layer 130 can be any suitable reagent layer including an enzymatic reagent layer. Reagent layer 130 can contain, for example, an oxido-reductase enzyme (such as glucose oxidase), GDH-PQQ, GDH-FAD, a catalase, a peroxidase (such as horse radish peroxidase), and an alcohol dehydrogenase. It could also include buffer salts (such as phosphate, Pipes, and HEPES), a mediator (such as ferricyanide, hexamineruthenium chloride, ferrocene compounds, and polymeric mediators (e.g., polyacrylamide covinyl ferrocene).

[0029] However, it is noted that reagent layer 130 can include any suitable enzymatic reagents, with the selection of enzymatic reagents being dependent on the analyte to be determined. For example, if glucose is to be determined in a blood sample, reagent layer 130 can include a glucose oxidase or glucose dehydrogenase along with other components necessary for functional operation.

Reagent layer 130 can include, for example, glucose oxidase, tn-sodium citrate, citric acid, polyvinyl alcohol, hydroxyl ethyl cellulose, potassium ferrocyanide, antifoam, cabosil, PVPVA, and water. Further details regarding enzymatic reagent layers, and electrochemical-based analytical test strips in general, are in U.S. Patent Nos. 6,241,862 and 6,733,655, the contents of which are hereby fully incorporated by reference.

[0030] Patterned insulation layer 140 can be formed, for example, from a screen printable insulating ink. Such a screen printable insulating ink is commercially available from Ercon of Wareham, Massachusetts U.S.A. under the name "Insulayer." Patterned insulation layer 140 is electrically non-conductive and essentially insoluble in a bodily fluid sample of interest. Patterned insulation layer 140 can include a suitable dielectric polymer with pigment filler. Suitable dielectric polymers can include, for example, epoxy resins, vinyl resins, polyester resins, acrylic resins, polyurethane resins, or combinations thereof.

[0031] Top layer 160 can be formed of any suitable mater including, for example, polyester materials, polypropylene materials, other plastic materials or be a commercially laminate of a spacer and adhesive.

[0032] Electrochemical-based analytical test strip 100 can be manufactured, for example, by the sequential aligned formation of patterned conductor layer 120, reagent layer 130, patterned insulation layer 140, and top layer 160 onto electrically-insulating base layer 110. Any suitable techniques known to one skilled in the art can be used to accomplish such sequential aligned formation, including, for example, screen printing, photolithography, photogravure, chemical vapour deposition and tape lamination techniques. Moreover, electrochemical-based analytical test strip 100 can be manufactured using a web-based continuous manufacturing process.

[0033] FIG. 6 is a flow diagram depicting stages in a method 200 for determining an analyte (such as glucose) in a bodily fluid sample (for example, a whole blood sample) and/or a characteristics of the bodily fluid sample (e.g., hematocrit) according to an embodiment of the present invention.

[0034] Method 200 includes, at step 210, applying a bodily fluid sample to a capillary sample-receiving chamber of an electrochemical-based analytical test strip, the capillary sample-receiving chamber having disposed therein a working electrode of the electrochemical-based analytical test strip, a reagent layerof the electrochemical-based analytical test strip overlapping the working electrode, a counter electrode of the electrochemical-based analytical test strip, the counter electrode being devoid of the reagent layer and disposed in a co-planar configuration with the working electrode. The capillary sample-receiving chamber also has disposed therein a reagent diffusion bridge of predetermined dimensions of the electrochemical-based analytical test strip, the reagent-diffusion bridge adjoining the counter electrode and the reagent layer and defining a predetermined separation distance therebetween.

[0035] At step 220, magnitude and timing of at least a first electrochemical response of the analytical test strip are measured. The analyte is then determined based on the magnitude and timing of the first measured electrochemical response (see step 230).

[0036] With respect to methods and electrochemical-based analytical test strips according to the present invention, it should be noted that when the capillary sample-receiving chamber is initially tilled with a bodily tluid sample, the response is limited by the lack of reagent (e.g., mediator) at the counter electrode (which is devoid of the reagent layer). As reagent (e.g., mediator) diffuses across the reagent diffusion bridge trom the reagent layer to the counter electrode a peak in the magnitude of the response (for example, a peak current) will be obtained.

[0037] The magnitude and timing ot the electrochemical response (e.g., an amperometric response) depends on the amount of reduced mediator formed at the working electrode, the width of the reagent diffusion bridge, and the diffusivity of the mediator within the bodily fluid sample. Moreover, this diffusivity is correlated with the hematocrit ot the bodily fluid sample when the bodily fluid sample is a whole blood sample. The timing and magnitude ot the electrochemical response, which can include, tor example, the time taken to reach a peak current, can be employed in a determination of the analyte. Such a determination can employ an algorithm (for example, a two-factor interaction algorithm or higher polynomial algorithm) that corrects the analyte determination for hematocrit and/or other bodily tluid characteristic affects. In this way, accurate hematocrit-corrected analyte determinations can be accomplished.

[0038] Once apprised of the present disclosure, one skilled in the art will recognize that method 200 can be readily moditied to incorporate any of the techniques, benefits, features and characteristics of electrochemical-based analytical test strips according to embodiments of the present invention and described herein.

[0039] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that devices and methods within the scope of these claims and their equivalents be covered thereby. -14-

Claims

CLAIMS1. An electrochemical-based analytical test strip for the determination of at least one of an analyte in, and a characteristic of, a bodily fluid sample, the electrochemical-based analytical test strip comprising: an electrically-insulating base layer; a capillary sample-receiving chamber; a working electrode disposed on the electrically-insulating base layer in the capillary sample-receiving chamber; a reagent layer disposed on the electrically-insulating base layer in the capillary sample-receiving chamber and overlapping the working electrode; a counter electrode devoid of the reagent layer and disposed on the electrically-insulating base layer in the sample receiving chamber; a reagent diffusion bridge of predetermined dimensions disposed in the capillary sample-receiving chamber, the reagent diffusion bridge adjoining the counter electrode and the reagent layer and defining a predetermined separation distance therebetween; wherein the working electrode and counter electrode are disposed on the electrically-insulating base layer in a co-planar configuration.
2. The electrochemical-based analytical test strip of claim 1 further including: a patterned conductor layer disposed over the electrically-insulating base layer, the patterned conductive layer including the counter electrode and working electrode; a patterned insulation layer that includes the reagent diffusion bridge; a top layer, and wherein at least the electrically-insulating substrate layer, patterned conductor layer, patterned insulation layer, and top layer define the capillary sample-receiving chamber.
3. The electrochemical-based analytical test strip of claim 1 or claim 2 wherein the reagent diffusion bridge has a width in the range of 5Oum to 200um.
4. The electrochemical-based analytical test strip of claim 3 wherein the reagent diffusion bridge has a thickness in the range of 30 nanometers to 200 microns.
5. The electrochemical-based analytical test strip of any one of the preceding claims wherein the reagent diffusion bridge is a mediator diffusion bridge.
6. The electrochemical-based analytical test strip of any one of the preceding claims wherein the bodily fluid sample is a whole blood sample.
7. The electrochemical-based analytical test strip of any one of the preceding claims wherein the analyte is glucose.
8. The electrochemical-based analytical test strip of any one of the preceding claims wherein the top layer includes a capillary sample-receiving chamber-defining groove.
9. The electrochemical-based analytical test strip of any one of the preceding claims wherein the counter electrode is entirely devoid of reagents.
10. The electrochemical-based analytical test strip of any one of the preceding claims wherein the reagent diffusion bridge overlaps the reagent layer between the counter electrode and the working electrode.
11. A method for determining at least one of an analyte in a bodily fluid sample, the method comprising: applying a bodily fluid sample to a capillary sample-receiving chamber of an electrochemical-based analytical test strip, the capillary sample-receiving chamber having disposed therein: a working electrode of the electrochemical-based analytical test strip; a reagent layer of the electrochemical-based analytical test strip overlapping the working electrode; a counter electrode of the electrochemical-based analytical test strip, the counter electrode being devoid of the reagent layer and disposed in a co-planar configuration with the working electrode; and a reagent diffusion bridge of predetermined dimensions of the electrochemical-based analytical test strip adjoining the counter electrode and the reagent layer and defining a predetermined separation distance therebetween; and measuring magnitude and timing of at least a first electrochemical response of the electrochemical-based analytical test strip; and determining the analyte based on the magnitude and timing of the first measured electrochemical response.
12. The method of claim 11 wherein the bodily fluid sample is a whole blood sample.
13. The method of claim 11 or claim 12 wherein the analyte is glucose.
14. The method of any one of claims 11 to 13 wherein the first electrochemical response is an amperometric response.
15. The method of any one of claims 11 to 14 wherein the measuring of the amperometric response includes the measuring of current peak magnitude and current peak timing of the amperometric response.
16. The method any one of claims 11 to 15 wherein the determining step determines a hematocrit-corrected analyte concentration.
17. The method any one of claims 11 to 16 wherein the reagent layer is an enzymatic reagent layer containing a mediator and timing of the response is dependent on diffusion of the mediator across the reagent diffusion bridge.
18. The method any one of claims 11 to 17 wherein the determination step employs a 2-factor interaction algorithm to determine the analyte.
19. The method any one of claims 11 to 18 wherein the determination employs a polynomial equation to determine the analyte.
20. The method of any one of claims 11 to 19 wherein the reagent diffusion bridge has a width in the range of 5Oum to 200um and a thickness in the range of 30 nanometers to 200 microns.Amendments to the claims have been made as follows:CLAIMS1. An electrochemical-based analytical test strip for the determination of at least one of an analyte in, and a characteristic of, a bodily fluid sample, the electrochemical-based analytical test strip comprising: an electrically-insulating base layer; a capillary sample-receiving chamber; a working electrode disposed on the electrically-insulating base layer in the capillary sample-receiving chamber; a reagent layer disposed on the electrically-insulating base layer in the capillary sample-receiving chamber and overlapping the working electrode; a counter electrode devoid of the reagent layer and disposed on the electrically-insulating base layer in the sample receiving chamber; a reagent diffusion bridge of predetermined dimensions disposed in the C') 15 capillary sample-receiving chamber, the reagent diffusion bridge adjoining the counter electrode and the reagent layer and defining a predetermined separation distance therebetween; wherein the working electrode and counter electrode are disposed on the electrically-insulating base layer in a co-planar configuration.2. The electrochemical-based analytical test strip of claim 1 further including: a patterned conductor layer disposed over the electrically-insulating base layer, the patterned conductive layer including the counter electrode and working electrode; a patterned insulation layer that includes the reagent diffusion bridge; a top layer, and wherein at least the electrically-insulating substrate layer, patterned conductor layer, patterned insulation layer, and top layer define the capillary sample-receiving chamber.3. The electrochemical-based analytical test strip of claim 1 or claim 2 wherein the reagent diffusion bridge has a width in the range of 5Opm to 200pm.4. The electrochemical-based analytical test strip of claim 3 wherein the reagent diffusion bridge has a thickness in the range of 30 nm to 200 pm.5. The electrochemical-based analytical test strip of any one of the preceding claims wherein the reagent diffusion bridge is a mediator diffusion bridge.6. The electrochemical-based analytical test strip of any one of the preceding claims wherein the bodily fluid sample is a whole blood sample.7. The electrochemical-based analytical test strip of any one of the preceding claims wherein the analyte is glucose.8. The electrochemical-based analytical test strip of claim 2 wherein the top C') 15 layer includes a capillary sample-receiving chamber-defining groove.9. The electrochemical-based analytical test strip of any one of the preceding claims wherein the reagent diffusion bridge overlaps the reagent layer between the counter electrode and the working electrode. r10. A method for determining at least one of an analyte in, and a characteristic of, a bodily fluid sample, the method comprising: applying a bodily fluid sample to a capillary sample-receiving chamber of an electrochemical-based analytical test strip, the capillary sample-receiving chamber having disposed therein: a working electrode of the electrochemical-based analytical test strip; a reagent layer of the electrochemical-based analytical test strip overlapping the working electrode; a counter electrode of the electrochemical-based analytical test strip, the counter electrode being devoid of the reagent layer and disposed in a co-planar configuration with the working electrode; and a reagent diffusion bridge of predetermined dimensions of the electrochemical-based analytical test strip adjoining the counter electrode and the reagent layer and defining a predetermined separation distance therebetween; and measuring magnitude and timing of at least a first electrochemical response of the electrochemical-based analytical test strip; and determining the analyte based on the magnitude and timing of the first measured electrochem ical response.11. The method of claim 10 wherein the bodily fluid sample is a whole blood sample.12. The method of claim 10 or claim 11 wherein the analyte is glucose.13. The method of any one of claims 10 to 12 wherein the first electrochemical response is an amperometric response.C') 15 14. The method of claim 13 wherein the measuring of the amperometric response includes the measuring of current peak magnitude and current peak timing of the amperometric response. r15. The method any one of claims 10 to 14 wherein the determining step determines a hematocrit-corrected analyte concentration.16. The method any one of claims 10 to 15 wherein the reagent layer is an enzymatic reagent layer containing a mediator and timing of the response is dependent on diffusion of the mediator across the reagent diffusion bridge.17. The method any one of claims 10 to 16 wherein the determination step employs a 2-factor interaction algorithm to determine the analyte.18. The method any one of claims 10 to 17 wherein the determination employs a polynomial equation to determine the analyte.19. The method of any one of claims 10 to 18 wherein the reagent diffusion bridge has a width in the range of 5Opm to 200pm and a thickness in the range of 30 nm to 200 pm. C')N-r