Abstract:
A portable lancing aid for providing liquid samples comprises a lancet system having at least one lancet, a tensioning device, and an electromechanical actuator. The tensioning device can be tensioned by the electromechanical actuator. The portable lancing aid may further include an energy source for storing electrical energy that is connected to the electromechanical actuator. Additionally, the portable lancing aid may include an interface for charging the energy source where the interface is externally accessible from the lancet system. The invention is ergonomical and easy to handle for children and patients with physical limitations. Furthermore, a lancing system for collecting liquid samples is provided with a portable lancing aid that is detachably mountable to a charging station for charging the portable lancing aid.

Description:
RELATED APPLICATIONS 
     This is a continuation application of International Application PCT/EP2006/050530, filed Jan. 30, 2006, which claims priority to DE 10 2005 005 017.4, filed Feb. 3, 2005, which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     Monitoring blood glucose concentration is an essential part of the daily routine for diabetics. Blood glucose concentration must be determined rapidly and with ease several times daily in order to take appropriate medical measurements. In order to not restrict the daily routine of the diabetic more than necessary, mobile devices which are space-saving and simple to handle are used so that blood glucose concentration can be determined at any time. 
     Measurement of blood glucose concentration essentially requires two procedural steps. First, a liquid sample is generally produced by perforating the skin of the patient by means of a so-called lancet system, e.g., with the aid of a lancet needle driven by a spring system to generate a drop of blood. A blood quantity of 1.5 μL (or sometimes below 1 μL) is generally sufficient for modern measurement systems. Such lancet systems and lancing aids are known in the art and are commercially available in various embodiments. Such lancet systems are described, for example, in Publication Nos. DE 10 302 501 and DE 10 047 419. Lancing aids with magazine systems for holding and dispensing several lancets are also disclosed in these documents. 
     Second, the blood sample generated is then analyzed for blood glucose concentration. Diagnostic methods are usually used for this step and employ optical or electrochemical measuring methods. For example, a frequently used measuring method utilizes a special type of electrochemical test strip which can be designed such that a specified amount of blood is guided by a capillary system to an electrode system. This electrode system can, for example, be gold electrodes which are provided with a coating. The coating usually contains various enzymes and mediators and has the effect that charge carriers (for example, in the form of redox molecules) form within the blood sample at the electrodes. The concentration of the charge carriers are dependent on blood glucose concentration and can be determined by the gold electrodes and a suitable measuring system known to a person skilled in the art, for example, by means of a comparatively simple current-voltage measurement from which blood glucose concentration can be calculated. 
     Such a test device is known from U.S. Publication No. 20020170823, which can be used for substance analysis in body fluids such as for measuring blood glucose concentration. The described measuring device has a hand-held device and a base station in which the hand-held device and the base station can exchange data via an interface. The portable hand-held device is powered by lithium batteries. 
     In the first step described above for generating a blood sample, the lancet system usually first has to be manually tensioned when using systems and lancing aids known in the prior art. A spring system is typically manually tensioned, which requires a user to apply force in order to create the tension. However, this has disadvantages because children or people with physical limitations cannot usually use such lancing aids without help, and the use of such systems is inconvenient. Furthermore, operating some of these lancing aids with one hand is not always possible due to the required tensioning process. 
     SUMMARY OF THE INVENTION 
     Embodiments incorporating the present invention address the described disadvantages of the prior art and provide a portable lancing aid for collecting liquid samples and, in particular, for collecting blood samples for determining blood glucose concentrations. The portable lancing aid is easy to operate, especially for children or patients with physical limitations. Furthermore, additional embodiments provide a system for collecting liquid samples which has a portable lancing aid and a charging station for charging at least one long-term energy storage component of the portable lancing aid. 
     An exemplary embodiment of the portable lancing aid has at least one lancet system, wherein the lancet system has at least one lancet and at least one tensioning device for tensioning the lancet system. This lancet system can be one with a tensioning device that has a spring system such as those found in the prior art. This embodiment of the portable lancing aid is also flexible with regard to the design of the lancet and thus any lancet known to a person skilled in the art may be used. For example, the lancet can have at least one lancet needle, and in particular, a disposable lancet needle which for hygienic purposes is replaced by a new lancet needle after one or more lancing operations. Instead of lancet needles, the lancet can also have analogous designs such as prism-shaped, sharp-edged lancets. In particular, the portable lancing aid can have a single lancet or a plurality of lancets. In one embodiment with a plurality of lancets, a magazine for holding and/or dispensing lancets is advantageously used. An exemplary magazine is described in Publication No. DE 10 302 501. 
     In another embodiment, the portable lancing aid has at least one electromechanical actuator that tensions the tensioning device. The electromechanical actuator advantageously has at least one electric motor such as a direct current motor. It is further possible to use other electromechanical actuators such as magnetic systems (e.g., electromagnets) or piezoelectric systems. The electromechanical actuator can, for example, be directly connected to the lancet system, and in particular, with the tensioning device, or it can be connected by one or more gear units. The gear unit can, for example, have a drive mechanism via one or more drive belts or one or more gear wheels. 
     In addition, one embodiment of the portable lancing aid has at least one rechargeable long-term energy source that is connected to the electromechanical actuator in order to store electrical energy. In this embodiment, the energy source is used for storing electrical energy and remains substantially charged even after days if there is no electrical load. In particular, the electrical energy or charge should not decrease below 40% of the original energy or charge within about three days. This long-term energy source can be a battery and it has proven to be advantageous in various embodiments to use rechargeable batteries such as rechargeable lithium ion batteries and/or rechargeable lithium polymer batteries. It is also possible to use rechargeable nickel cadmium batteries and/or rechargeable nickel metal hydride batteries (NimH). However, it is also possible to use other types of rechargeable batteries. Thus, for example, capacitors having a long-term storage effect such as “supercaps” (also referred to as ultra capacitors) can also be used. Stored electrical energy can also be partially removed from these supercaps similar to batteries or rechargeable batteries and the self-discharge of these components is very low. Typical supercaps still have about 60-70% of their original charge after 30 days without load. Such components have the particular advantage over conventional rechargeable batteries in that they can be rapidly charged. 
     In another embodiment, the portable lancing aid has at least one interface that is accessible from outside the lancet system, wherein the long-term energy source can be connected to the interface in order to store electrical energy and be recharged. This interface can be one or more electrodes, such as metal electrodes, which are arranged on the outside of the housing. An appropriate complementary interface (e.g., a charging interface or charging station) can then be used to supply energy to these metal electrodes via connection to an appropriate power supply unit. This allows the energy source of the portable lancing aid to be recharged at regular intervals. 
     In another embodiment, the interface can also have a device for inductively charging the long-term energy source. For example, the interface can have a secondary coil of a transformer that is electrically connected to the energy source and a transformer core such that the energy source can be inductively charged essentially by putting a primary coil on the transformer core and applying an alternating voltage to this primary coil. This primary coil can, for example, be a component of a charging station into which the portable lancing aid is inserted. 
     The charging operation can take place when a charge level indicator shows that the charge level is below the minimum charge value for the long-term energy source. Hence, it has proven to be advantageous in one embodiment when the portable lancing aid has a charge level indicator to display the electrical charge level of the energy source for storing electrical energy. Such charge level indicators are known to a person skilled in the art and can, for example, have simple optical displays and/or acoustic indicators. In particular, the charge level indicator can have an optical segment display in the form of one or more light-emitting diodes which indicate the charge level of the energy source. Furthermore, the user of the portable lancing aid can also be given a warning such as an alarm such as an optical or acoustic signal when the charge level of the energy source reaches or falls below a specified minimum charge level. Thus, the user can be warned when the charge level of the energy source is no longer adequate to tension the lancet system or when the charge level is only sufficient for a few tensioning operations (for example, enough energy for a daily number of blood glucose measurements). This prevents the user or patient from not being able to carry out blood glucose measurements due to an unexpectedly uncharged energy source of the portable lancing device. 
     Embodiments of the portable lancing aid are advantageous over lancing aids in the prior art because the user no longer has to exert any mechanical force to tension the lancet system. The lancet system is instead tensioned by the electromechanical actuator. Hence, the portable lancing aid can also be used comfortably by patients with physical limitations or by children. The portable lancing aid can also be easily operated with one hand. If the charge level of the energy source and, in particular of the rechargeable battery, falls below a specified minimum value, the user or patient is warned accordingly so that the energy source can either be recharged or replaced. In addition, an embodiment of the device can also be provided in which the tensioning device is manually tensioned so that the lancet system can still be tensioned even when the energy source is empty or almost empty, but in this case the patient has to exert a mechanical force. 
     In an exemplary embodiment, the portable lancing aid can include at least one tensioning status sensor which detects the tensioning state of the tensioning device. Furthermore, means can be provided such as an appropriate electronic device or element (e.g., a microcomputer or other electronic components) to analyze the detected state of tension of the tensioning device. A tensioning operation can then be triggered depending on the detected state of tension. If it is, for example, found that the lancet system is in an untensioned state (e.g., after the lancet system has been triggered), the tensioning device can be automatically retensioned. The portable lancing aid is thus again ready for operation and further intervention by the user is not necessary. This embodiment is especially advantageous in combination with a portable lancing aid having a magazine for holding a plurality of lancets. In this embodiment, the system is designed such that a new lancet is selected automatically for each tensioning operation and prevents unhygienic multiple use of the same lancet. In an alternative embodiment, the lancet can be selected manually by the user, for example, by means of an appropriate rotary knob connected to the magazine. 
     In an advantageous embodiment, the system for collecting liquid samples includes a charging station to charge the long-term energy source of the portable lancing aid. In this embodiment, one or more portable lancing aids can be connected to a charging station. Such charging stations are known from various fields of the state of the art. In addition to the base station disclosed in U.S. Publication No. 20020170823, such systems are also disclosed in U.S. Pat. No. 6,524,240 for charging portable medical devices. An example of an electronic circuit of a charging station which prevents a portable instrument that is inserted into the charging station from being actuated when a charging current flows is disclosed in Publication No. DE 4036479. 
     The charging station can, for example, have at least one charging interface or coupling which can be connected to a source of electrical energy. This connection can be via one or more switches (for example selection switches or on/off switches) or via an electronic circuit so that an appropriate voltage transformation, an overvoltage protection, and/or an appropriate interval timer can be used which simplifies the handling of the system and makes a safer design. In this embodiment, it should be possible to connect the portable lancing aid to the charging station such that the charging interface or coupling is connected to the interface of the portable lancing aid. This connection between the portable lancing aid and the charging station can be accomplished by inserting the portable lancing aid into a corresponding recess of the charging station where the portable lancing aid is advantageously aligned during insertion such that the interface of the portable lancing aid is in electrical contact with the interface or coupling of the charging station. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned aspects of the present invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of the embodiments of the invention, taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a portable lancing aid with a portion of the external housing partially removed; 
         FIG. 2  is a perspective view of a system for collecting liquid samples showing the portable lancing aid of  FIG. 1  and a charging station; 
         FIG. 3  is a top view of the charging station of  FIG. 2 ; and 
         FIG. 4  is a flow chart illustrating a method for collecting blood samples for determining blood glucose concentration. 
     
    
    
     Corresponding reference numerals are used to indicate corresponding parts throughout the several views. 
     DETAILED DESCRIPTION 
     The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention. 
       FIG. 1  shows a perspective view of an embodiment of a portable lancing aid  110 . The portable lancing aid  110  has a housing  112  which is shown partially removed in  FIG. 1  for the purpose of illustration. A housing cover  114  (see  FIG. 2 ) can be removed from the remaining housing  112  in order to open the housing  112  by loosening screws  116  (see  FIG. 2 ) which connect the housing cover  114  to the remaining housing  112  by appropriate threaded holes  118 . 
     The portable lancing aid  110  additionally has a lancet system  120 . The design and mode of operation of this lancet system  120  can, for example, be analogous to the embodiment of the lancet system  120  disclosed in U.S. Pat. No. 7,223,276. Other embodiments of lancet systems can be used such as the lancet system disclosed in U.S. Publication No. 20040260325. The aforementioned U.S. patent and publication are hereby incorporated by reference. 
     The lancet system  120  has a tensioning device  122  and a release or trigger button  124 . In addition, the lancet system  120  has a drum magazine  126  (mostly hidden in  FIG. 1 ) to hold several disposable lancets  128  (not shown). An exemplary drum magazine  126  is described in U.S. Publication No. 20060008389, which is hereby incorporated by reference. The lancet system  120  also has a lancet cap  130  which has an exit hole in the front face (not shown) for the lancet  128  to extend through. The lancet cap  130  is designed to be detached from the lancet system  120  so that the drum magazine  126  can be replaced by removing the lancet cap  130 . Furthermore, the lancing depth of the lancets  128  can be adjusted by rotating the lancet cap  130 . The drum magazine  126  can be adjusted by means of a rotary knob  132  on the end of the lancet system  120  and thus a new and unused lancet  128  can be selected. In this embodiment, a disposable lancet  128  is selected manually by the user. In an alternative embodiment, a device can be provided in which a new disposable lancet  128  is selected from the drum magazine  126  after each lancing operation. 
     The portable lancing aid  110  also has a direct current motor  134  in the embodiment shown in  FIG. 1 . The direct current motor  134  is connected to the tensioning device  122  of the lancet system  120  by means of a drive  136  having two gear wheels  138 ,  140 . Thus, the tensioning device  122  of the lancet system  120  can be tensioned by means of the direct current motor  134 . As described above, other electromechanical actuators such as magnetic actuators, piezoactuators or other complex types of motors such as stepping motors can be used. 
     As shown in  FIG. 1 , the portable lancing aid  110  has a tensioning status sensor  142  which can detect the tensioning state of the tensioning device  122 . In this embodiment, the tensioning status sensor  142  is a sensor which detects the position of the gear wheel  140  and according to this position determines whether the tensioning device  122  is tensioned. This tensioning status sensor  142  can, for example, also be a component of the direct current motor  134  where an angular position of the direct current motor  134  is determined by the position of the gear wheels  138 ,  140  and/or the drive  136 . The tensioning status can be detected if a stepping motor is used instead of a direct current motor  134 . However, stepping motors are relatively complicated. Two or more tensioning status sensors  142  can be used instead of an individual status sensor  142  where, for example, a first tensioning status sensor  142  detects the tensioned status of the tensioning device  122  and a second tensioning status sensor  142  detects the untensioned status of the tensioning device  122 . 
     The portable lancing aid  110  shown in  FIG. 1  has a rechargeable lithium ion battery  144  and an electronic control circuit board or element  146 . The rechargeable lithium ion battery  144  supplies the direct current motor  134  and the electronic control circuit board or element  146  with electrical energy. The high energy density of the rechargeable lithium ion battery  144  typically allows up to about 100 tensioning operations of the tensioning device  122  by the direct current motor  134  with minimal battery size. Furthermore, the discharge of such rechargeable lithium ion batteries  144  is relatively low and thus average use of the portable lancing aid  110  (typically between five and fifteen times per day) requires only periodic recharging of the rechargeable lithium ion battery  144 . 
     The electronic control circuit board or element  146  of the portable lancing aid  110  is designed such that the tensioning status of the tensioning device  122  detected by the tensioning status sensor  142  is used to automatically tension the lancet system  120 . As soon as the tensioning status sensor  142  detects that the tensioning device  122  of the lancet system  120  is in an untensioned state (e.g., after triggering the lancet system  120 ), the direct current motor  134  is started automatically by the electronic control circuit board or element  146  so that the tensioning device  122  is retensioned and the portable lancing aid  110  is thus again ready for operation. Other embodiments of the portable lancing aid  110  are possible in which tensioning the tensioning device  122  by the direct current motor  134  is not triggered until the user makes an affirmative action such as by actuating an appropriate input button on the surface of the portable lancing aid  110 . 
     In the embodiment shown in  FIG. 1 , the portable lancing aid  110  has an interface  148  which is arranged on the electronic control circuit board or element  146  and protrudes through the housing cover  114  when the housing  112  is closed and can thus be accessed from the outside. This interface  148  can have one or more metal contacts. The rechargeable lithium ion battery  144  can be electrically charged via this interface  148 . Furthermore, the portable lancing aid  110  can also be designed such that information can be exchanged via the interface  148 , for example, in order to supply the electronic control circuit board or element  146  with information about the patient (e.g., information about the lancing depth of the lancet system  120 ). 
     An embodiment of a system for collecting liquid samples  210  is shown in  FIG. 2 . The system  210  has a portable lancing aid  110  according to the embodiment shown in  FIG. 1  (with a closed housing cover  114 ) and a charging station  212 . The portable lancing aid  110  is inserted into an appropriately shaped recess  214  of the charging station  212 . This charging station  212  is also shown from above in  FIG. 3  where the recess  214  is better illustrated. The charging station  212  has a housing  216  into which the recess  214  forms, and the recess is designed such that the housing  112  of the portable lancing aid  110  can be inserted therein. In this arrangement, the interface  148  of the portable lancing aid  110  is in electrical contact with a charging interface or coupling  310  of the charging station  212  when the portable lancing aid  110  is inserted into the charging station  212 . The charging interface or coupling  310  is further connected to a main connection or power cord  218 . The charging interface or coupling  310  is advantageously not directly connected to the main connection or power cord  218 , but rather via an appropriate electronic circuit that can have switches, an overvoltage protection, a voltage transformer, and/or other electronic components. This ensures that when the portable lancing aid  110  is inserted into the charging station  212 , the rechargeable lithium ion battery  144  of the portable lancing aid  110  is electrically charged and is not damaged by incorrect handling or electrical interferences (power fluctuations or short circuits). 
     The charging station  212  is additionally provided with a flat underside or bottom surface  220  such that the charging station  212  can be safely positioned on flat surfaces without tilting even after the portable lancing aid  110  is inserted. Other exemplary charging stations  212  may have several recesses  214  and charging interfaces or couplings  310  to simultaneously charge several portable lancing aids  110  for use, such as, in hospitals. 
       FIG. 2  also shows that the portable lancing aid  110  has a charge level indicator  222  on the housing cover  114 . This charge level indicator  222  can also be positioned at other sites on the housing  112  and is designed as a segment display having five light-emitting diodes in this embodiment. For example, all five light-emitting diode segments may light up corresponding to the highest charge status of the rechargeable lithium ion battery  144  and none of the segments of the charge level indicator  222  may light up corresponding to the rechargeable lithium ion battery  144  being completely discharged. The light-emitting diode segments can, for example, also have different colors to indicate a low charge status to the user. In particular, the charge level indicator  222  can be actuated by the electronic control circuit board or element  146 . 
       FIG. 4  shows an exemplary method where the system  210  of  FIG. 2  is used to collect liquid samples. The steps shown in  FIG. 4  do not necessarily have to be carried out in the order shown and other steps that are not shown can also be performed. 
     In describing the steps involved in the method of  FIG. 4 , reference is made to the embodiments shown in  FIGS. 1 and 2 . In the first step  410 , a disposable lancet  128  is selected, for example, by means of the rotary knob  132  of the portable lancing aid  110  of  FIG. 1 . In the second step  412 , the tension of the tensioning device  122  is detected by means of a tensioning status sensor  142 . Subsequently, the detected tensioning status is checked in step  414 . If it is determined (step  416 ) that the tensioning device  122  is in an untensioned state, step  418  is carried out and the tensioning device  122  is tensioned by means of the direct current motor  134 . If, in contrast, it is determined in step  414  that the tensioning device  122  is already in a tensioned status (step  420 ), then step  418  (tensioning of the lancet system  120 ) is skipped. The lancet system  120  is now ready for operation and is triggered in step  422  (for example, by pressing the trigger button  124 ). 
     The detection of the tensioning status in step  412  and checking the tensioning status in step  414  can be carried out continuously or periodically so that the lancet system  120  is kept in a tensioned state. Alternatively, as described above, the tensioning  418  of the lancet system  120  can also be initiated by user input. 
     Finally in step  424 , the charge status of the rechargeable lithium ion battery  144  is detected. This detection of the charge status in step  424  does not necessarily take place after the triggering step  422 , but rather the detection of the charge status can also, for example, be carried out continuously or at regular intervals or at other stages in the method of  FIG. 4 . The charge status is indicated to a user of the portable lancing aid  110  in step  426  by means of the charge level indicator  222 . A query can also be carried out in step  428  in which the charge status is checked to determine whether the charge status is below a specified minimum charge value. If the charge falls below the minimum charge value (step  430 ), the user is alerted in step  432 , for example, by an acoustic or optical warning signal. Subsequently in step  434 , the rechargeable lithium ion battery  144  is recharged by inserting the portable lancing aid  110  into the charging station  212  as shown in  FIG. 2 , and the charging station  212  is supplied with electrical energy via the main connection or power cord  218 . 
     While exemplary embodiments incorporating the principles of the present invention have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. 
     LIST OF REFERENCE NUMERALS 
     
         
           110  portable lancing aid 
           112  housing 
           114  housing cover 
           116  screws 
           118  threaded holes 
           120  lancet system 
           122  tensioning device 
           124  trigger button 
           126  drum magazine 
           128  disposable lancets 
           130  lancet cap 
           132  rotary knob 
           134  direct current motor 
           136  drive 
           138  gear wheel 
           140  gear wheel 
           142  tensioning status sensor 
           144  rechargeable lithium ion battery 
           146  electronic control circuit board or element 
           148  interface 
           210  system for collecting liquid samples 
           212  charging station 
           214  recess 
           216  housing of the charging station 
           218  mains connection or power cord 
           220  flat underside 
           222  charge level indicator 
           310  charging interface or coupling 
           410  selection of a lancet 
           412  detection of a tensioning status 
           414  checking the tensioning status 
           416  untensioned status 
           418  tensioning of the lancet system 
           420  tensioned status 
           422  triggering the lancet system 
           424  detecting a charge status 
           426  indicating the charge status 
           428  checking whether it falls below the minimum charge status 
           430  falls below the minimum charge status 
           432  output of a warning signal 
           434  charging