Abstract:
A bio-measuring meter is provided. The bio-measuring meter includes a receptacle receiving a sample strip for the bio-measuring meter; and a figured piece identifying device comprising plural switches for receiving a figured piece, wherein at least one of the plural switches is switched by the figured piece to generate a current signal, and a datum of the sample strip is adjusted by a predefined respective parameter for the current signal.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to bio measuring meters for determining the presence of an analyte in a biological sample, and more particularly, to a bio measuring meter whose operation is controlled by a code provided by a removably pluggable coding module. The present invention further relates to a coding module pluggable into a bio measuring meter for receiving a sample strip. The coding module defines at least one code, the code ciphering at least one property that is employed in controlling the operation of the meter, for example by controlling the operation of the meter. The invention further relates to a set of coding modules, to a method for producing coding modules, to a bio measuring system, to a bio measuring test set and to a method for operating a bio measuring meter in accordance with the claims. 
       BACKGROUND OF THE INVENTION 
       [0002]    Bio measuring meters applied for detecting substances contained in blood to be analyzed, such as glucose or cholesterol, use a disposable sample strip. The sample strip has a reaction zone allowing blood to be placed thereon. The operation is controlled by a microprocessor. By execution of various methods, analysis results of the measurement are obtained. 
         [0003]    For processing the sample measurement and the analysing routines the bio measuring meter needs certain parameter values which determine thresholds, time intervals, control numbers and calibration curve attributes. 
         [0004]    Usually it is necessary to calibrate measuring devices in order to compensate for variations from lot to lot of the manufactured sample strip. Various techniques have been suggested for encoding information into the sample strip, as disclosed by U.S. Pat. No. 5,053,199 and references cited therein. This may e.g. be electronically encoded information on a carrier having an optical bar code, a magnetizable film, a perforated strip, a fluorogens or an electrically conductive medium on a foil. 
         [0005]    Each of such known sample strips has to be furnished with an in-formation code, which is an additional manufacturing step and thus an expensive effort for a disposable device. 
         [0006]    Other conventional measuring meters use an additional coding module or code key designed and inserted into a receptacle similar to the slot for the sample strip. 
         [0007]    When performing a measurement, the memory key has to be inserted in the measuring meter before using a new batch of sample strips. Preferably the coding module remains inserted during the measurement or even all the time for the same batch of sample strips. 
         [0008]    Based on the data or the code provided by the coding module the operation method, parameters or algorithms are chosen and a correct measurement result is obtained. 
         [0009]    U.S. Pat. No. 5,366,609 and documents cited therein disclose bio measuring meters which have pluggable ROM coding modules that enable re-configuration of test methods and parameters employed by the meter. Threshold potentials, test times, delay periods and other pertinent test methods and constants may be entered and/or altered. 
         [0010]    The main purpose of the coding module still is to provide information about the type of sample strip. For each new batch of sensor strips, new related information is needed. 
         [0011]    As sample strips are disposable, preferably coding modules are disposable too. Costs for the module are therefore an important factor. 
         [0012]    In a co-pending application, a coding module and bio measuring meter are presented, wherein the code is represented by a parameter value of an electrical component having a determined characteristic, such as a resistor or a capacitor. In comparison with the use of integrated circuits, the use of electrical components reduces the complexity and cost of the design. Thus, some of the drawbacks of the state of the art are overcome. However, the costs due to components and fabrication are still relatively high. Furthermore, electrical components present a risk of being influenced by a contamination of biological samples. Cleaning of such a code key is not easily feasible. 
         [0013]    It is therefore an object of the invention to overcome the drawbacks of the prior art, especially to avoid the usage of memory IC chip technology for storing codes on coding modules, and to provide a coding module, a set of coding modules, a method for producing a coding module, a bio measuring meter with pluggable coding module, a bio measuring system, a bio measuring test set and a method for operating a bio measuring meter, which are not sensible with regard to a pollution caused by a biological sample and which can be produced cost-effectively. 
       SUMMARY OF THE INVENTION 
       [0014]    In accordance with the present invention, a coding module is presented, which is connectable with a bio measuring meter for receiving a sample strip. The coding module defines at least one code. The code ciphers at least one property that is usable during operation of the meter. The at least one code is represented by at least one figured element. 
         [0015]    According to the present invention, a figured element is an element having an outer structure which is mechanically ascertain-able. The at least one figured element typically can have an identifiable form, shape or surface texture. Preferably, the at least one figured element is arranged at a predefined position of the coding module. These positions define a coding area on the coding module. 
         [0016]    The property usable on operation of the meter can be a set of parameter values that is employed in controlling the operation of the meter, for example by defining an evaluation curve or a parameter value for the choice of a predefined evaluation procedure or an input for a microprocessor routine. 
         [0017]    A coding module being connectable with a bio measuring meter can be brought into measuring contact with the meter once, repeatedly or can remain attached thereto. 
         [0018]    One advantage of using figured elements for encoding information is that the coding module can be integrally formed. No further steps for adding or fixing electric or electronic components are necessary which results in a cost-effective fabrication. 
         [0019]    Whereas in the conventional coding modules, the code is mostly represented by electromagnetic characteristics, and the figured elements according to the present invention have mechanical characteristics which are not influenced by electromagnetic fields or chemical pollution. 
         [0020]    The coding module according to the present invention can be completely free of electronic or electromagnetic components for coding purposes, which leads to a cost reduction by a saving of components and additional fabrication steps. Because of the lack of such components, the module can easily be cleaned. However, electronic or electric contacts may be present for other purposes. 
         [0021]    Preferably, the at least one figured element is able to activate a switch and/or to engage with a switch on a meter. The switch can be activated directly, for example by the figured element closing or interrupting an electrical connection. Alternatively the switch could be activated indirectly, for example electro-magnetically based on e.g. optical, tactile or electric detection of the figured element. 
         [0022]    The coding area of the coding module could also be coated with a second material, for example a conductive layer, thus resulting in an electro-magnetically or optically detectable pattern. 
         [0023]    To allow the engagement with a switch on the bio measuring meter the at least one figured element is preferably formed by a projecting element, for example a protrusion, a tine, a tooth and/or pin, and/or an incising element, for example a cut, a recess and/or a hole. Figured elements of these types can simply be added to a basic form of a coding module but can also easily be formed in a production step when a coding module is integrally made in one piece. Moreover, the coding module can be integrally formed with the sample strip. 
         [0024]    In a preferred embodiment, the at least one code is represented by a number and an arrangement of figured elements, preferably representing a binary code of 1 to 10 digits, more preferably of five digits. Thus the presence or the absence of a certain shaped element can simply be translated to a zero or one in a binary code and thus to one or more numbers. These numbers can for example be used for accessing data from a look up table such as to receive associated parameter values. 
         [0025]    The coding module can have a receptacle able to receive the sample strip. The receptacle can allow a direct electrical coupling between the sample strip and the bio measuring meter. Alternatively the coding module can have an electrical coupling for connecting the sample strip and the bio measuring meter. 
         [0026]    In both alternatives, the samples strip might come into contact with the coding module which leads to the danger of a pollution caused by the biologic sample. The coding represented by at least one figured element is not disturbed by a possible contamination with biologic sample or analyte. In case of a contamination, the function of the coding module is not affected. Furthermore, a one piece coding module can easily be cleaned and sanitized without influencing the coding elements and thus a continued use is allowed. 
         [0027]    According to a further aspect of the invention, there is provided a set of coding modules, particularly of the above described type, with at least two types of coding modules, wherein the coding modules differ in the number, in the shape and/or in the arrangement of their figured elements. Thus, each coding module defines a different code, ciphering parameter values being related to a certain sample strip batch. 
         [0028]    After fabrication of a series of samples strips, the samples strips can be measured and be divided into batches, which batches are associated with certain members of the set of coding modules. 
         [0029]    According to a further aspect of the invention, there is provided a method for producing a coding module or a set of coding modules, preferably of the above described type comprising the step of moulding of a coding module in a mould, wherein the mould is designed to provide at least one figured element. 
         [0030]    The coding module can e.g. be injection moulded. Other processes, e.g. compression moulding, are also possible. The figured elements can be integrally formed or elements can be formed which can be subsequently used to form figured elements, for example a perforation which allows to remove parts of the coding area. 
         [0031]    To fabricate a set of coding modules, the mould can be completely exchanged and the mould can be replaced by a different one featuring different figured elements. Preferably, the mould is modified only on parts. 
         [0032]    For example, only the part of the mould forming the at least one figured element representing the code is replaced by a different part designed to form a further code. After moulding coding modules with a second code, the mould can be modified again. By using this method, it is possible to fabricate a set of coding modules. 
         [0033]    Since for different encodings only parts of the mould have to be exchanged, this method is cost-effective with regard to the investment and preproduction cost. 
         [0034]    Instead of exchanging or modifying the mould to fabricate coding modules with different encodings, it is also possible to fabricate a basic coding module preformed by moulding. 
         [0035]    In a second fabrication step, a code representation is provided by adding, removing and/or changing at least one figured element, wherein the code representation corresponds to a certain type of sample strips. 
         [0036]    This adaptation can be carried out by a mechanical post processing, for example by drilling, cutting or removing at least one prepared part of the coding area. 
         [0037]    According to another aspect of the invention, a bio measuring meter for receiving a sample strip is provided, the bio measuring meter having a receptacle able to accept a pluggable coding module. The bio measuring meter comprises means for receiving information from the coding module defining at least one code. The means comprises means for measuring at least one figured element representing the code. 
         [0038]    The coding module is preferably of the above described type, wherein the code is represented by a number an arrangement of figured elements. 
         [0039]    The bio measuring meter is provided with information about the sample strip batch by the code on the coding module. 
         [0040]    The code can be a simple binary code, defining a code number and being interpreted as one of a variety of sets of parameter values stored in the bio measuring meter. The encoding can be made more complex by using a bigger number of figured elements or by different types of figured elements, such as holes and protrusions. 
         [0041]    The determination of the code based on measuring of the figured elements and the translation of the code into parameter values used during operation is performed by the bio measuring meter. The coding module is only a carrier of the code. The bio measuring meter has the capability of reading the code, decoding and using the information. The parameter values can be derived from the code by a microprocessor routine or can be extracted using a look-up table stored in a memory of the bio measuring meter. 
         [0042]    Preferably the bio measuring meter comprises mechanical, electromagnetic and/or optical means for reading the code, measuring the at least one figured element of the coding module. 
         [0043]    In a preferred embodiment, the bio measuring meter comprises at least one switch, activable by the at least one figured element. More preferably, the bio measuring meter comprising as many switches as positions for figured elements are arranged on the coding module, such that each position of a figured element corresponds to a switch and each figured element interacts with a corresponding switch. 
         [0044]    The bio measuring meter may have different receptacles for the sample strips and the coding module. Alternatively the bio measuring meter may comprise one receptacle able to accept a coding module formed to allow or to provide an electrical connection between the sample strip and the bio measuring meter. 
         [0045]    According to a further aspect of the invention, there is provided a bio measuring system for analysing an analyte, comprising at least one coding module with at least one code, preferably of the above described type and comprising a bio measuring meter, preferably of the above described type, with means for receiving the at least one code from the the coding module. The code ciphers at least one parameter value that is used in controlling the operation of the bio measuring meter, for example in control-ling the execution of an algorithm performed by the meter that enables determination of an analyte concentration value. The at least one code is represented by at least one figured element and the bio measuring meter comprises means for measuring at least one figured element representing the code. 
         [0046]    The bio measuring system can comprise a set of coding modules, each having a different code being associated with a certain batch of sample strips. 
         [0047]    According to a further aspect of the invention, there is provided a bio measuring test set, comprising at least one test strip, and comprising a coding module with at least one code, preferably of the above described type, being associated with the at least one test strip and pluggable into a bio measuring meter. The code ciphers at least one parameter value that is used in controlling the operation of the bio measuring meter when analysing the test strip, for example in controlling the execution of an algorithm performed by the meter that enables determination of an analyte concentration value. The at least one code is represented by at least one figured element. 
         [0048]    Usually, a bio measuring test set comprising one coding module and a plurality of samples strips form a commercial unit which is sold together in one package. 
         [0049]    According to a further aspect of the invention, there is provided a method for operating a bio measuring meter, preferably of the above described type, comprising the steps of (i) inserting a coding module with at least one code into the bio measuring meter; (ii) detecting the at least one code; (iii) determining at least one parameter value used for control-ling operation of the meter; (iv) inserting a sample strip and adding a biologic sample; and (v) analysing the sample on the basis of the at least one parameter value. The detecting of the at least one code is carried out by measuring at least one figured element arranged on the module. 
         [0050]    Although the present invention is presented in the context of a clinical or diagnostic instrument, it has utility in calibration of other medical measurement devices as well. 
         [0051]    The present invention may be more fully understood by referring to the following detailed description of illustrative embodiments thereof and the accompanying drawings thereof. 
         [0052]    The above contents and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0053]      FIG. 1   a  is a perspective top view of a first example of a bio measuring meter incorporating the present invention; 
           [0054]      FIG. 1   b  is a perspective bottom view of a first example of a bio measuring meter incorporating the present invention; 
           [0055]      FIG. 2  is a schematic representation of a first embodiment of the present invention; 
           [0056]      FIG. 3   a  is a top view of a first example of a coding module according to the present invention and corresponding switches of a meter according to the present invention; 
           [0057]      FIG. 3   b  is a top view of the example of  FIG. 3   a  with a coding module inserted in the meter; 
           [0058]      FIG. 4   a  is a side view of a switch and a coding module; 
           [0059]      FIG. 4   b  is a sectional view of the switch engaged with a figured element from  FIG. 3   b  along A-A; 
           [0060]      FIG. 4   c  is a sectional view of the switch engaged with a figured element from  FIG. 3   b  along B-B; 
           [0061]      FIGS. 5   a - 5   e  are schematic views of different embodiments of figured elements on a coding module according to the present invention; 
           [0062]      FIG. 6   a  is a perspective top view of a second example of a bio measuring meter incorporating the present invention with an inserted sample strip and coding module; 
           [0063]      FIG. 6   b  is a perspective top view of the example of  FIG. 6   a  without the sample strip; 
           [0064]      FIG. 6   c  is a perspective top view of the example of  FIG. 6   a  with a removed module; 
           [0065]      FIG. 7   a  is a perspective top view of a second example of a coding module according to the present invention and measuring means according to the present invention; 
           [0066]      FIG. 7   b  is a perspective bottom view of a second example of a coding module according to the present invention; 
           [0067]      FIG. 8  is a perspective top view of a third example of a bio measuring meter incorporating the present invention; and 
           [0068]      FIGS. 9   a - 9   g  are schematic views of different embodiments of figured elements on a sample strip according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0069]    Referring to  FIG. 1 , a bio measuring meter  100  has a display  111 , an operation button  112  and a receptacle  113  able to receive a disposable sample strip  200 . The sample strip  200  has a reaction zone which contains conductive electrodes. A reactant layer (not shown) is formed in the reaction zone to cover the electrodes. An analyte-containing fluid, for example a drop of blood, can be dripped on a substance entrance  220 . 
         [0070]    The bio measuring meter  100  further has a second receptacle  114  for receiving a coding module  10 , which is inserted into the receptacle  114  of the bio measuring meter  100 . 
         [0071]    When the coding module  10  is plugged into the slot  114  of the bio measuring meter  100 , measuring means of the bio measuring meter  100  get into contact with figured elements  30   a,    30   b,  . . .  30   n  of the coding module  10 . 
         [0072]      FIG. 1   b  is a perspective bottom view of a first example of a bio measuring meter  100  with the inserted coding module  10 . 
         [0073]      FIG. 2  schematically shows a meter  100  with a coding module  10  according to the present invention and with a test strip  200 . The meter  100  comprises standard components such as a microprocessor with a central processing unit, a read-only memory and a random accessible memory, a display, a current measuring unit, an electrode working voltage supply unit and a temperature measuring unit. Those elements are standard in state of the art devices. In addition, the meter comprises a resistance measuring unit  150  which on the one hand is in operative connection with the microprocessor and on the other hand is connected to switches  156   a,    156   b,  . . . ,  156   n  for measuring figured elements  30   a,    30   b,  . . .  30   n  in the coding module  10 . The arrangement of figured elements  30   a  to  30   n  ciphers a certain code as will be shown hereinafter. Detection of the figured elements  30   a,    30   b,  . . .  30   n  is made in a manner known to those skilled in the art, in particular by measuring a current in order to determine whether the switches  156   a,    156   b,  . . . ,  156   n  are open or closed. Analog/digital converters are used to transmit the current values to the micro-processor. 
         [0074]      FIG. 3   a  is a top view of a first example of a coding module  10  and measuring means  155  in form of five switches  156   a,    156   b,  . . . ,  156   e  of a meter. The switches  156   a,    156   b,  . . . ,  156   e  are in electrical contact with a common potential at a conductor  157 . Without the coding module  10  being inserted, the switches  156   a,    156   b,  . . . ,  156   e  are in contact with a second conductor  158 . Thus all switches  156   a,    156   b,  . . . ,  156   e  are “closed” able to allow passing a predefined current. 
         [0075]    The coding module  10  in  FIG. 3   a  has figured elements  30   a,    30   b,  . . . ,  30   e  in the form of cuts  31 , which are arranged in a coding area  32  at certain positions  33   a,  . . . ,  33   e  of the coding module  10 . The number and the arrangement of the cuts represent a five-digit binary code. 
         [0076]    When the coding module  10  is inserted in the bio measuring meter  100 , the figured elements  30   a,    30   b,  . . . ,  30   e  come into contact with the measuring means  155  as shown in  FIG. 3   b.    
         [0077]    Each position  33   a,  . . . ,  33   e  of a figured element  30   a,    30   b,  . . . ,  30   n  corresponds to a switch  156   a,    156   b,  . . . ,  156   e.  All switches  156   a,    156   b,  . . . ,  156   e  are opened, i.e. the contact between the conductors  158  and  157  is interrupted, by inserting the coding module  10  except those switches  156   a  and  156   d,  at which corresponding positions  33   a,    33   d  cuts  31  are arranged on the coding module  10 . 
         [0078]    A current is thus flowing through switches  156   a,    156   d.  This current can be sensed by measuring the voltage difference across a resistor, not explicitly shown in this Figure, connected in series with the switches. 
         [0079]      FIG. 4   a  is a side view of a switch  156  and a coding module  10 , when the coding module is not inserted. The switch  156  is in a closed position, resulting in a current. The current leads to a difference of potential across a resistance  159  connected in series with the switch  156 . 
         [0080]      FIG. 4   b  is a sectional view of  FIG. 3  along A-A. Switch  156   b  is engaged with a figured element  30   b  of the coding module  10 . The switch  156   b  now is in an open position, and the current is interrupted. 
         [0081]      FIG. 4   c  is a sectional view of  FIG. 3  along B-B. Switch  156   d  of the coding module  10  meets a cut  31  at the position  33   d  associated with the switch  156   d.  Thus the switch  156   d  is in a closed position, when the coding module  10  is inserted. 
         [0082]    The current flowing through switches  156   a - 156   e  of the meter  100  is related to the arrangement and the number of the cut  31 . The code represented by the figured elements on the coding module  10  can thus be detected. 
         [0083]    Different embodiments of figured elements on a coding module  10  are shown in  FIGS. 5   a  to  5   e,  for example slots  34  in  FIG. 5   a,  ribs  35  in  FIG. 5   b,  holes  36  in  FIG. 5   c,  dents  37  in  FIG. 5   d  and bumps  38  in  FIG. 5   e.    
         [0084]    The front area  40  of the coding module  10  is tapered to ease the insert and the opening of the switches. 
         [0085]    Referring to  FIGS. 6   a  to  6   c,  in a second example of the present invention, the measuring meter  101  has one receptacle  115  for receiving the sample strip  200  and the coding module  11 . 
         [0086]    The coding module  11  allows an electrical connection between the bio measuring meter  101  and the sample strip  200 . When the coding module  11  is plugged into the bio measuring meter  101 , the sample strip can be inserted in a slot  116  of the same receptacle  115  and electrical contacts  50  on the coding module  11  get in contact with the electrodes of the sample strip  200 . 
         [0087]      FIG. 7   a  is a perspective top view of the coding module  11  with a coding area  32  and electrical contacts  50  and measuring means  155 . When the coding module  11  is inserted in the measuring meter, the coding area  32  with the figured elements  30   a,    30   b,  . . . ,  30   n  engages with the switches  156   a,    156   b,  . . . ,  156   n,  whereas the electrical contacts  50  get in contact with electrode contacts  160 . 
         [0088]      FIG. 7   b  is a perspective bottom view of the coding module  11  with electrical contacts  50 . 
         [0089]    When the coding module  11  and the sample strip  200  are inserted in the measuring meter  101 , the contacts  50  on the coding module  11  get in electrical contact with the electrodes of the sample strip. In a similar manner, contacts  160  of the meter  101  are brought into electrical contact with the contacts  50  of the coding module  11  and consequently with the electrodes of the sensor strip  200 . 
         [0090]    This embodiment makes sure that the meter can not be operated without a module  11  properly inserted. 
         [0091]    Alternatively, the electrical contact between the electrodes on the sample strip and the electrode contacts  161  in the meter  102  can be made without conductive means on the coding modules  12 , as shown in  FIG. 8 . The coding module  12  comprises a recess  60  which allows the electrode contacts  161  of the meter  102  to get in electrical connection with the electrodes of the sample strip, when the coding module  12  is inserted in the meter  102 . 
         [0092]    Different embodiments of figured elements integrally formed with the sample strip  200 , i.e. the figured elements  91 ˜ 97  are directly mounted on the sample strip  200 , are shown in  FIGS. 9   a ˜ 9   g.  Each time while the sample strip  200  is inserted, the states of the switches are switched corresponding to the figured elements  91 ˜ 97  and the code represented by the figured elements on the sample strip  200  can thus be detected. 
         [0093]    While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.