Patent Application
20160320328
The present invention relates, in general, to medical devices and, in particular, to test meters and related methods.
The determination (e.g., detection and/or concentration measurement) of an analyte in, or characteristic of, a bodily fluid sample is of particular interest in the medical field. For example, it can be desirable to determine glucose, ketone bodies, cholesterol, lipoproteins, triglycerides, acetaminophen, haematocrit and/or HbA1c concentrations in a sample of a bodily fluid such as urine, blood, plasma or interstitial fluid. Such determinations can be achieved using a hand-held test meter in combination with analytical test strips (e.g., electrochemical-based analytical test strips).
According to one aspect of the present invention there is provided a hand-held test meter for use with an electrochemical-based analytical test strip in the determination of an analyte in a bodily fluid sample. The hand-held test meter comprises a housing; a micro-controller disposed in the housing; an operating range test strip simulation circuit block disposed in the housing; and a strip port connector configured to operationally receive an electrochemical-based analytical test strip. The operating range test strip simulation circuit block is in electrical communication with the strip port connector; and the operating range test strip simulation circuit block is configured to simulate an electrochemical-based analytical test strip inserted into the strip port connector and an operating range of bodily fluid samples applied to the electrochemical-based analytical test strip by sequentially presenting a plurality of electrical loads. Each of the plurality of electrical loads is configured as a first resistor of predetermined value in series with a parallel configuration of a second resistor of predetermined value and a first capacitor of predetermined value. The strip port connector is configured in electrical communication with the micro-controller.
The test strip and applied bodily fluid sample circuit block of the hand held test meter may be configured to simulate a plurality of applied bodily fluid samples across either a glucose operating range of the hand-held test meter, a hematocrit operating range of the hand-held test meter or a combined glucose and hematocrit operating range of the hand-held test meter. The test strip and applied bodily fluid sample circuit block may be the operating range test strip simulation circuit block.
In one embodiment, the hand-held test meter may comprise twelve electrical loads.
In any embodiment, the first resistor in each of the plurality of electrical loads in the hand-held test meter may be essentially identical.
The plurality of operating loads of the hand-held test meter may simulate an operating range that includes a design and manufacturing guard band which may be +/−30%.
In one embodiment, the first resistor may have a predetermined value of 5,100 ohms, the second resistor may have a predetermined value in the range of 16,000 ohms to 390,000 ohms, and the first capacitor may have a predetermined value in the range of 0 pF to 6.2 pF or in the range of 0 pF to 8.2 pF.
In one embodiment, the plurality of electrical loads may share the first resistor.
The electrochemical-based analytical test strip of the hand-held test meter may be configured for the determination of glucose in a whole blood bodily fluid sample.
The operating range test strip simulation circuit block of the hand-held test meter may be further configured to simulate an electrochemical-based analytical test strip inserted into the strip port connector and an operating range of control solutions applied to the electrochemical-based analytical test strip by sequentially presenting the plurality of loads.
A second aspect of the present invention is a method for employing a hand-held test meter for use with an electrochemical-based analytical test strip in the determination of an analyte in, or a characteristic of, a bodily fluid sample. The method comprises employing an operating range test strip simulation circuit block of a hand-held test meter by activating the operating range test strip simulation circuit block; presenting in a sequential manner, to a port connector of the hand-held test meter by the operating range test strip simulation circuit block, upon the activating of the operating range test strip simulation circuit block, a plurality of electrical loads. Each of the plurality of electrical loads are configured as a first resistor of predetermined value in series with a parallel configuration of a second resistor of predetermined value, and a first capacitor of predetermined value. The plurality of electrical loads spans the working range of the hand-held test meter with respect to a predetermined bodily fluid sample and at least one of an analyte in the bodily fluid sample and characteristic of the bodily fluid sample.
The employing and presenting of the above method may serve to test operation of the hand-held test meter prior to use of the hand-held test meter for the determination of an analyte.
The method may further include the steps of inserting an electrochemical-based analytical test strip into the hand-held test meter following the presenting and subsequently determining at least one of an analyte in, and a characteristic of, a bodily fluid sample applied to the analytical test strip using a micro-controller of the hand-held test meter.
The test strip and applied bodily fluid sample circuit block may be configured to simulate a plurality of applied bodily fluid samples across a glucose operating range of the hand-held test meter, a hematocrit operating range of the hand-held test meter or a combined glucose and hematocrit operating range of the hand-held test meter.
The plurality of electrical loads of the above method may be twelve electrical loads.
The first resistor of in each of the plurality of electrical loads may be essentially identical.
The plurality of operating loads may simulate an operating range that includes a guard band, which may be +/−30%.
The first resistor may have a predetermined value of 5,100 ohms, the second resistor may have a predetermined value in the range of 16,000 ohms to 390,000 ohms, and the first capacitor may have a predetermined value in the range of 0 pF to 6.2 pF.
The plurality of electrical loads may share the first resistor.
The electrochemical-based analytical test strip may be an electrochemical-based analytical test strip configured for the determination of glucose in a whole blood bodily fluid sample.
The operating range test strip simulation circuit block may be further configured to simulate an electrochemical-based analytical test strip inserted into the strip port connector and an operating range of control solutions applied to the electrochemical-based analytical test strip by sequentially presenting the plurality of loads.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings, in which like numerals indicate like elements, of which:
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.
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.
In general, hand-held test meters for use with an electrochemical-based analytical test strip in the determination of an analyte (such as glucose) in, and/or a characteristic (for example, hematocrit) of, a bodily fluid sample (such as for example, a whole blood sample) according to embodiments of the present invention include a housing, a micro-controller disposed in the housing, an operating range test strip simulation circuit block disposed in the housing and a strip port connector configured to operationally receive an electrochemical-based analytical test strip. The operating range test strip simulation circuit block is in electrical communication with (for example, electrically connected in a direct or indirect manner) the strip port connector. In addition, the operating range test strip simulation circuit block is configured to simulate an electrochemical-based analytical test strip inserted into the strip port connector and an operating range of bodily fluid samples applied to such an electrochemical-based analytical test strip by sequentially presenting a plurality of electrical loads. Each of the plurality of electrical loads is configured as a first resistor in series with a parallel configuration of a second resistor and a first capacitor. Moreover, the strip port connector is configured in electrical communication with the micro-controller.
Hand-held test meters according to embodiments of the present invention are beneficial in that the operating range test strip simulation circuit block is configured such that a simulation of an entire operating range of an analyte in a bodily fluid sample (such as glucose in a whole blood sample) and/or a characteristic of an bodily fluid sample (for example, hematocrit of a whole blood sample) can be performed, thus fully testing proper operation of the hand-held test meter across the operating range. In some embodiments, the plurality of electrical loads also beneficially tests the operating range of control solutions conventionally employed to test operation of the hand-held test meter. In addition, such hand-held test meters are beneficial in that the operating range test strip simulation circuit block can be employed to easily and repeatedly test operation of the hand-held test meter without the need for, or the variation induced by, an actual electrochemical-based analytical test strip and a plurality of control solutions that mimic bodily fluid samples across the entire operating range of the hand-held test meter.
Once one skilled in the art is apprised of the present disclosure, he or she will recognize that an example of a hand-held test meter that can be readily modified as a hand-held test meter according to the present invention is the commercially available OneTouch® Ultra® 2 glucose meter from LifeScan Inc. (Milpitas, Calif.). Additional examples of hand-held test meters that can also be modified are found in U.S. Patent Application Publications No's. 2007/0084734 (published on Apr. 19, 2007) and 2007/0087397 (published on Apr. 19, 2007) and in International Publication Number WO2010/049669 (published on May 6, 2010), and Great Britain Patent Application No. 1303616.5, filed on Feb. 28, 2013, each of which is hereby incorporated herein in full by reference.
Referring to
Display 102 can be, for example, a liquid crystal display or a bi-stable display configured to show a screen image. An example of a screen image during the determination of an analyte in a bodily fluid sample may include a glucose concentration, a date and time, an error message, and a user interface for instructing a user how to perform a test. Examples of screen images during use of the operating range test strip simulation circuit block may be an image reporting that a hand-held test meter operating range test passed, or an image reporting that the hand-held test meter operating range test has resulted in an error.
Strip port connector 106 is configured to operatively interface with an electrochemical-based analytical test strip TS, such as an electrochemical-based analytical test strip configured for the determination of hematocrit and/or glucose in a whole blood sample. Therefore, the electrochemical-based analytical test strip is configured for operative insertion into strip port connector 106 and to operatively interface with micro-controller block 112 via, for example, suitable electrical contacts, wires, electrical interconnects or other structures known to one skilled in the art.
USB Interface 108 can be any suitable interface known to one skilled in the art. USB Interface 108 is an electrical component that is configured to power and provide a data line to hand-held test meter 100.
Micro-controller block 112 also includes a memory sub-block that stores suitable algorithms for the determination of an analyte based on the electrochemical response of an analytical test strip and to also determine a characteristic (e.g., hematocrit) of the introduced bodily fluid sample. Micro-controller block 112 is disposed within housing 110 and can include any suitable micro-controller and/or micro-processor known to those of skill in the art. Suitable micro-controllers include, but are not limited to, micro-controllers available commercially from Texas Instruments (Dallas, Tex., USA) under the MSP430 series of part numbers; from ST MicroElectronics (Geneva, Switzerland) under the STM32F and STM32L series of part numbers; and Atmel Corporation (San Jose, Calif., USA) under the SAM4L series of part numbers).
Operating range test strip simulation circuit block 114 is in electrical communication with strip port connector 106 (see
Moreover, operating range test strip simulation circuit block 114 is configured to simulate an inserted electrochemical-based analytical test strip and an operating range of bodily fluid samples applied thereto by sequentially presenting a plurality of electrical loads with each of the plurality of electrical loads configured as (i) a first resistor of predetermined value in series with (ii) a parallel configuration of a second resistor of predetermined value, and a first capacitor of predetermined value. In addition, the plurality of electrical loads spans the operating range of the hand-held test meter with respect to a predetermined bodily fluid sample (such as a whole blood sample) and at least one of an analyte in the bodily fluid sample (for example, glucose) and characteristic (e.g., hematocrit) of the bodily fluid sample.
Referring to
Table 1 below provides an exemplary, but non-limiting, tabulation of first resistor, second resistor and first capacitor values for twelve (12) electrical loads as can be employed in an operating range test strip simulation circuit block according to the present invention. In the embodiment of
The values of Table 1 provide electrical loads that simulate an electrochemical-based test strip with an applied operating range for whole blood samples with hematocrit levels ranging from 29.3% to 55.2%. The predetermined values of Table 9 were experimentally determined for an electrochemical-based analytical test strip with electrical traces having a resistance of 5,100 ohm (hence the Rs value of 5,100 ohm) and an operating frequency of 75 KHz. The experimental determination included collecting signal phase and magnitude across the operating range and converting these values to resistive and capacitive elements (i.e., Rp and Cp) through calculation and added to the known strip electrical characteristic (i.e., Rs) to build a model of a whole blood sample across the hematocrit range and independent of glucose concentration. The maximum and minimum values of Rp and Cp for the first nine rows of Table 1 (i.e., n=1 through 9) include an additional 30% margin as a design and manufacturing guard band for the hand-held test meter electronics. The final 3 rows of Table 1 (i.e., n=10 through 12) are values that were determined in a similar manner as the first nine rows but represent three electrical loads that cover the operating range for control solution measurements. Similar experimental techniques can also be used to determine Rs, Rp and Cp values across the operating for any suitable analyte in a bodily fluid sample such as, for example, glucose in whole blood samples. Therefore, if a plurality of loads corresponding to Table 1 is employed, the operating range test strip simulation circuit block is considered to be further configured to simulate an electrochemical-based analytical test strip inserted into the strip port connector and an operating range of both hematocrit and control solutions applied to the electrochemical-based analytical test strip by sequentially presenting the plurality of loads.
Once apprised of the present disclosure, one skilled in the art will recognize that that embodiments of the present invention can be readily configured by modification of the hand-held test meters described in co-pending Great Britain Patent Application No. 1303616.5, filed on Feb. 28, 2013, which is hereby incorporate in full be reference.
Method 500 includes employing an operating range test strip simulation circuit block of a hand-held test meter by activating the operating range test strip simulation circuit block (see step 510 of
In method 500, the plurality of electrical loads spans the operating range of the hand-held test meter for a predetermined bodily fluid sample and at least one of an analyte in the bodily fluid sample and/or characteristic of the bodily fluid sample.
Once apprised of the present disclosure, one skilled in the art will recognize that methods according to embodiments of the present invention, including method 500, can be readily modified to incorporate any of the techniques, benefits and characteristics of hand-held test meters according to embodiments of the present invention and described herein.
Once apprised of the present disclosure, one skilled in the art will recognize that the meters and methods according to embodiments of the present invention, including method 600, can employ any suitable electrochemical techniques, including those based on Cottrell current measurements, coulometry, amperometry, chronoamperometry, potentiometry, and chronopotentiometry.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1322927.3 | Dec 2013 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/079064 | 12/22/2014 | WO | 00 |
