Abstract:
An apparatus and a method for measuring a property of a blood sample is shown. The apparatus comprises of a housing having an aperture; a shaft mounted inside the housing; a testing member rotatably mounted on the shaft; an actuating member coupled to the housing and configured to exert a force against the testing member; and a lancet for eliciting a blood sample fixedly coupled to and protruding substantially radially from the testing member and configured to co-rotate with the testing member. The apparatus is further configured such that the lancet is aligned with the aperture in the housing when the testing member is in a first position. The testing member is configured, in the presence of a force exerted against the testing member by the actuator member, to translate to a second position in which the lancet is in a skin penetrating position.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. application Ser. No. 13/808/306, filed Jun. 27, 2013, which is a U.S. National Phase Application pursuant to 35 U.S.C. §371 of International Application No. PCT/EP2011/061538 filed Jul. 7, 2011, which claims priority to European Patent Application No. 10168956.0 filed on Jul. 8, 2010. The entire disclosure contents of these applications are herewith incorporated by reference into the present application. 
     
    
     FIELD OF INVENTION 
       [0002]    This invention relates to apparatus and method for allowing measurements to be made of a blood sample. The invention relates also to apparatus comprising a blood analysis part for receiving a blood sample. 
       BACKGROUND 
       [0003]    Diabetes sufferers may be provided with quantities of insulin, for instance by injection, sometimes a number of times daily. The quantity of insulin that is appropriate depends on the person&#39;s blood glucose level, so blood glucose level measurement can also occur a number of times daily. 
         [0004]    Blood glucose level measurement typically is a multi stage process. The first is lancing, in which a lancet, or needle, is used to pierce the skin of a user, for example on the end or side of a finger. Once a suitable amount of blood has been produced, a sample is taken on a testing strip. A person may need to squeeze their finger in order to cause sufficient blood to be expelled. Sometimes lancing needs to be reperformed. The testing strip then is provided to a meter, typically an electronic meter, which analyses the sample, for example by determining a parameter (e.g. an electrochemical potential or voltage, resulting from a chemical reaction between the blood sample and an enzyme present in the testing strip, and provides a blood glucose measurement result. This measurement is then used to determine an amount of insulin to be consumed by the person. 
         [0005]    Lancing can be painful or at least uncomfortable for a user. Numerous efforts have been made to reduce or minimise discomfort to a user in the lancing process. More effective efforts typically involve more complicated, and thus more expensive, mechanical or electro-mechanical arrangements. 
       SUMMARY 
       [0006]    According to a first aspect of the invention there is provided apparatus for eliciting a blood sample, the apparatus comprising: 
         [0007]    a housing having an aperture; 
         [0008]    a shaft mounted inside the housing; 
         [0009]    a testing member rotatably mounted on the shaft; 
         [0010]    an actuating member coupled to the housing and configured to exert a force against the testing member; and 
         [0011]    a lancet fixedly coupled to and protruding substantially radially from the testing member and configured to co-rotate with the testing member; 
         [0012]    wherein the apparatus is configured such that the lancet is aligned with the aperture in the housing when the testing member is in a first position, and 
         [0013]    wherein the testing member is configured, in the presence of a force exerted against the testing member by the actuator member, to translate to a second position in which the lancet is in a skin penetrating position. 
         [0014]    This can allow particularly effective lancing to be achieved whilst allowing the advantages that can be experienced by use of a testing member that is rotatably mounted on a shaft. 
         [0015]    The testing member may further comprise a blood sample collection part. Such a combined lancing and blood collection apparatus can reduce the number of actions needed by a user to perform a blood parameter measurement, such as a blood glucose measurement. 
         [0016]    According to a second aspect of the invention there is provided a method of eliciting a blood sample, the method comprising: 
         [0017]    rotating a testing member on a shaft mounted inside a housing to a first position so as to align a lancet protruding substantially radially from the testing member with an aperture in the housing, and 
         [0018]    an actuator member exerting a force against the testing member to translate the testing member to a second position in which the lancet is in a skin penetrating position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
           [0020]      FIG. 1  is a perspective view of a blood glucose meter (BGM) according to aspects of the invention. 
           [0021]      FIG. 2  is a perspective view of the BGM of  FIG. 1  with a portion shown as transparent, so as to allow features inside a housing to be seen; 
           [0022]      FIG. 3  is the same as  FIG. 2  although a lid portion is shown as being removed; 
           [0023]      FIG. 4  is the same as  FIG. 3 , although a cartridge is shown as partly removed; 
           [0024]      FIG. 5  illustrates components of a BGM that is outside the scope of the claims but includes features of embodiments of the invention; 
           [0025]      FIG. 6  is a perspective view of components of the BGM of  FIG. 5  but with a hollow cylindrical housing part shown as transparent; 
           [0026]      FIG. 7  is a perspective view of a test disc member forming part of the BGM of  FIGS. 1 and 5 ; 
           [0027]      FIG. 8  is an underneath perspective view of the test disc member of  FIG. 7 ; 
           [0028]      FIGS. 9 to 12  illustrate the BGM of  FIGS. 5 to 7  at different stages of a blood collection sample process; 
           [0029]      FIG. 13  illustrates components of BGM of  FIG. 1  embodying aspects of the invention in a perspective view; 
           [0030]      FIG. 14  illustrates a test disc member forming part of the  FIG. 13  embodiment; 
           [0031]      FIGS. 15 to 18  illustrate the embodiment of the BGM of  FIG. 13  at different phases of operation; 
           [0032]      FIG. 19  is a perspective view of components of the BGM of  FIG. 1 ; 
           [0033]      FIG. 20  is the same as  FIG. 19 , although with a hollow cylindrical housing part not shown; 
           [0034]      FIG. 21  is the same as  FIG. 20  although with a swing arm located in a different position; and 
           [0035]      FIG. 22  is a flowchart illustrating operation of the BGM of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    A blood glucose meter (BGM)  100  is shown in  FIG. 1 . The BGM  100  is shown in a perspective view. The BGM  100  has a generally flat base, that is not visible in the figure. The BGM  100  is approximately as tall as it is long, and its width is approximately one-third of its height 
         [0037]    On one side face of the BGM are provided first, second and third inputs  101 ,  102 ,  103 . These may take the form of push-switches or touch sensitive transducers, for instance. Also provided on the side of the BGM next to the input devices  101  to  103  is a display  104 . This may take any suitable form, for instance a liquid crystal display (LCD), e-ink etc. In use, a user may control the BGM  100  using the input devices  101  to  103  and may be provided with information by the BGM through the display  104 . 
         [0038]    Located at a front face of the BGM  100  is an aperture  105 . The aperture  105  is located at approximately half of the height of the BGM. The aperture  105  is configured such as to be able to receive a part of a user&#39;s body, for the purpose of extracting a blood sample therefrom. For instance, the aperture  105  may be dimensioned so as to receive an end or a side part of a finger or thumb, or may be dimensioned so as to receive a side of a user&#39;s hand or a pinch of skin from a user&#39;s arm. The aperture may be rectangular in shape. Its edges may be beveled, so as to guide a user&#39;s digit into a specific location. 
         [0039]    The aperture  105  is provided in the side of a cartridge  106 . The cartridge has a generally cylindrical form, and is arranged vertically in the BGM  100 . 
         [0040]    In particular, the BGM includes a first housing part  107 . The first housing part  107  forms the base, left and right side face and the rear face of the BGM  100 . On the front face of the BGM  100 , the first housing part  107  also comprises the lowermost part of the side face. A fixed lid part  108  is attached to the first housing part  107 . The fixed lid part  108  comprises most of the top surface of the BGM  100 . A removable lid part  109  comprises the remaining part of the top surface of the BGM  100 . The removable lid part is disposed above the cartridge  106  at the front face of the BGM  100 . 
         [0041]    The first housing part  107  is configured such as to provide an elongate aperture  110  at the front face of the BGM  100 . The elongate aperture  110  may extend for most of the height of the front face of the BGM  100 . The elongate aperture  110  is defined at the uppermost part by the removable lid part  109  and is defined by the first housing part  107  at the right, left and bottom. The BGM  100  is arranged such that the cartridge  106  occupies the whole of the area of the elongate aperture  110 . A slidable or pivotable door in the housing part  107  of the BGM  100  may cover all or a part of the elongate aperture  110  when the BGM is not in use. The door may cover at least the aperture  105 , such as to prevent the ingress of dirt and other potential contaminants into the aperture  105   
         [0042]    The cartridge  106  is more clearly visible in  FIG. 2 .  FIG. 2  shows the same view as  FIG. 1 , although the removable lid part  109  and the first housing part  107  are shown in wire frame. As can be seen from  FIG. 2 , the cartridge  106  has a generally cylindrical form, and is arranged vertically. The diameter of the cartridge  106  is greater than the width of the aperture  110  by a factor for instance of between 5 and 50%. The cartridge  106  has a length that is between 3 or 4 times its diameter. 
         [0043]    In  FIG. 3 , the removable lid part  109  is shown as having been removed from the BGM  100 . The first housing part  107 , the fixed lid part  108  and the removable lid part  109  are configured such that when the removable lid part is in place on the BGM the cartridge  106  is retained by mechanical interaction between the three components but is removable by a user. The exact way in which the removable lid part  109  is released from the BGM  100  is not critical and is not described in detail here. 
         [0044]    The removable lid part  109  is configured such that when removed from the BGM  100  the cartridge  106  is able to be extracted from the BGM by moving it vertically along its axis. In  FIG. 4 , the cartridge  106  is shown as being partly removed from the BGM  100 . When fully removed, the elongate aperture  110  reveals a cavity in the BGM  100 . A replacement cartridge can then be introduced into the BGM  100  in the opposite manner to which the old cartridge  106  was removed. Once located at the bottom of the cavity in the BGM, the new cartridge  106  is partly surrounded by the first housing part  107 . Once the removable lid part  109  has been replaced, to the position shown in  FIG. 1 , the cartridge  106  is retained in place by the action of the first housing part  107  and the removable lid part  109 . The aperture  105  in the cartridge  106  is presented at the front face of the BGM  100 , in the same way as shown in  FIG. 1 . The cartridge  106  and the cavity which receives the cartridge may have a keying feature, such as a protrusion and a groove, a non circular diameter, or the like. Thus, when the cartridge  106  is fully inserted, the aperture  105  is in a fixed position to the elongate aperture  110 , for example in a centered position as shown in  FIG. 1 . 
         [0045]      FIG. 5  shows a subsystem  200  of the blood glucose meter  100 . The subsystem  200  includes the cartridge  106 , a drive wheel  201  and a drive belt  202 . 
         [0046]    In  FIG. 5 , the cartridge shown as having a hollow cylindrical housing part  203 , which constitutes part of a housing. The aperture  105  is formed in the hollow cylindrical housing part  203 . Coaxial with the hollow cylindrical part  203  is an elongate shaft  204 , only the top part of which is illustrated in  FIG. 5 . The length of the shaft  204  is such that its uppermost end is slightly below the uppermost end of the hollow cylindrical housing part  203 . As will be described below, the shaft  204  is mechanically coupled with the drive belt  202  so as to be rotatable by rotation of the drive wheel  201 . 
         [0047]    Formed with the inner surface of the hollow cylindrical housing part  203  are first and second guide members  205 ,  206 . In  FIG. 5 , it can be seen that the first and second guide members  205 ,  206  have a generally triangular cross section. One side of the triangular cross section of the first and second guide members  205 ,  206  is integral with the inner surface of the hollow cylindrical housing part  203 , with a point of the triangular cross section extending towards the centre of the cartridge  106 . A part of the length of the first guide member  205  is visible in  FIG. 5 , but only the uppermost surface of the second guide member  206  is visible in that figure. 
         [0048]      FIG. 5  also shows some electronic components that form parts of the blood glucose meter  100 . These components are provided within the housing  107  but do not form part of the cartridge  106 . 
         [0049]    A bus  211  is arranged to connect a number of components including a microprocessor  212 , random access memory (RAM)  213 , read-only memory (ROM)  214 , a keys interface  215 , a display driver  216 , an analyte interface circuit  219  and a motor interface  217 . All of these components are powered by a battery  218 , which may take any suitable form. 
         [0050]    Stored in the ROM  214  is software and firmware that governs operation of the blood glucose meter  100 . The software/firmware is executed by the microprocessor  212  using the RAM  213 . The software/firmware stored in the ROM  214  is operable to operate the blood glucose meter  100  such as to allow control by a user through the keys or input devices  101  to  103 , as detected by the keys interface  215 . A blood glucose measurement and other information is provided on the display  104  at suitable times by operation of the software/firmware and the microprocessor  212  through the display driver  216 . 
         [0051]    The motor interface  217  allows the microprocessor  212 , according to the software/firmware stored in the ROM  214 , to control the motor that is coupled to the drive wheel  201 , and any other motors that are included in the blood glucose meter  100  (as will be described below). 
         [0052]    The analyte interface circuit  219  is operable to provide electrical signals with certain voltages to the electrical contact terminals  401 , and thus the contact pads  318  and thus the analyte measuring part  316 , and to measure parameters of signals such as to allow the microprocessor  212  to determine a blood glucose level of a blood sample. 
         [0053]      FIGS. 6 to 12  are outside the scope of the claims but provide useful explanation of some features of embodiments of the invention. 
         [0054]      FIG. 6  shows the drive wheel  201  and cartridge  106  of  FIG. 5  with the hollow cylindrical housing part  203  shown in wire frame, so as to reveal components internal to it, and in that the electronic components are omitted. In  FIG. 6 , a third guide member  207  is visible. As can be seen from this figure, the first and second guide members  205 ,  206  are located only in the uppermost half of the length of the cartridge  106 , and the third guide member  207  is located only in the lowermost half of the cartridge  106 . The first, second and third guide members  205  to  207  are distributed around the circumference of the hollow cylindrical housing part  203 . In particular, the first and second guide members  205 ,  206  are located at approximately 100 to 160 degrees from one another. The third guide member  207  is located approximately 60 to 130 degrees from each of the first and second guide members  205 ,  206 . 
         [0055]    Mounted on the shaft  204  are a plurality of members, three of which are shown in  FIGS. 6  as  208 ,  209  and  210  respectively. The members  208  to  210  will hereafter be referred to as test disc members. Each of the test disc members  208  to  210  is substantially the same. 
         [0056]    One test disc member  208  is shown in some detail in  FIG. 7 . The test disc member  208  has a generally circular shape, although on one side a notch  301  is formed and on another side a cutaway portion  302  is provided. The cutaway portion  302  constitutes a milking portion. 
         [0057]    The test disc member  208  includes an uppermost surface  303 , a lowermost surface  304 , which is shown in  FIG. 8 , and a disc edge  305 . The diameter of the test disc member  208  is between 15 and 25 millimetres, for instance 20 millimetres. The thickness of the disc, which is equal to the height of the disc edge  305 , is between 0.5 millimetres and 1 millimetre.  FIG. 8  shows the test disc member  208  from the underside. As such, the lower surface  304  is visible and the upper surface  303  is not visible. The test disc member  208  will now be described with reference to  FIGS. 7 and 8 . 
         [0058]    A hole  306  is formed at the centre of the test disc member  208 . The hole  306  comprises two main parts. A circular part is centered on the test disc member  208  and has a diameter equal to or slightly larger than the external diameter of the shaft  204 . A drive notch  307  abuts the circular part of the hole  306  and includes edges that are able to be engaged by a drive dog. 
         [0059]    A drive dog  320  (visible in part in  FIG. 9  and more fully in  FIG. 10 ) is formed on the shaft  204 . The drive dog  320  is engaged with the drive notch  307  in the hole  306  of the test disc member  208 . This engagement allows rotation of the shaft  204  to result in rotation of the test disc member  208 . 
         [0060]    On the underside of the test disc member  208  is provided a spacer member  308 . The spacer member  308  comprises a slice of a hollow cylinder. The cylinder is centered on the centre of the test disc member  208 . The inner diameter of the spacer member  308  is selected such that the hole  306  does not overlap with the spacer member  308 . The outer diameter of the spacer member  308  is only slightly greater than the inner diameter, so the spacer member  308  has little thickness. The height of the spacer member  308  is between 0.5 and 1 millimetre. When plural test disc members are stacked together, the spacer member  308  provides separation between the upper surface  303  of one test disc member and the lower surface  304  of the test disc member that is directly above it. The separation is determined by the height of the spacer member  308 . 
         [0061]    Referring again to  FIG. 7 , a lancet  309  is shown protruding from the disc edge  305 . The lancet  309  is provided in the cutaway portion  302 . A first end of the lancet  309  is embedded within the material of the test disc member  208 , and a second end is provided with a sharp point and extends outwardly. The lancet  309  extends at an angle between 30 and 60 degrees from a radius line of the test disc member  208  at the position where the end of the lancet  309  is embedded in the test disc member. The second end of the lancet  309  is located at or just outside a circumference  311  of the test disc member  208 . The circumference  311  is shown as a dotted line in  FIG. 7  because it is virtual, instead of tangible. The lancet  309  extends from the disc edge  305  at a first position  312  on the disc edge. The first position  312  is close to a second position  313  at which the cutaway portion  302  starts. The cutaway portion  302  ends at a third position  314 . Between the second and third positions  313 ,  314  opposite to the cutaway portion  302 , the disc edge  305  generally takes the form of a circle, although the notch  301  interrupts that circle. 
         [0062]    Located next to the third position  314  is a blood collection part  315 . This may take any suitable form. For instance, it may comprise a laminated material. The blood collection portion  315  has the function of drawing blood that is in contact with the disc edge  305  at the third position into the test disc member  208  to an blood analyte measuring part  316 , that adjoins the blood collection part  315 , for example a part containing an enzyme for blood glucose measuring, or the like. Blood may be drawn through capillary action. The analyte measuring part  316  includes an enzyme that reacts chemically with blood in such a way that blood glucose level can be measured. The analyte measuring part  316  is connected to first to third contact pads  318  by first to third conductive tracks  317 . The contact pads  318  and the conductive tracks  317  are formed on the upper surface  303  of the test disc member  208 . The analyte measuring part  316  analyte measuring part  316 also is formed on the upper surface  303  of the test disc member  208 . Some or all of the conductive tracks  317 , the contact pads  318  and the analyte measuring part  316  may be printed onto the upper surface  303  of the test disc member  208 . In an alternative embodiment, the test disc member  208  may have only 2 contact pads. In yet another embodiment, the test disc member  208  may have more than 3 contact pads, for example, 4 or 5 contact pads. 
         [0063]    In use a part of a user is firstly pierced by the lancet  309 , the part is then milked by the disc edge  305  at the cutaway portion  302 , and blood then is provided to the analyte measuring part  316  through the blood collecting portion  315 . A measuring circuit connected to the analyte measuring part  316  by way of the conductive tracks  317  and the contact pads  318  then is able to determine a blood glucose level of the user. The level then is displayed on the display  104 . 
         [0064]    Operation will now be described with reference to the figures. 
         [0065]    As shown in  FIG. 6 , the test disc members  208  to  210  commence at the same orientation. Here, the first test disc member  208  is uppermost. The third guide member  207  is located in the notch  301  of the lowermost test disc members  209 ,  210 . The notch  301  of the first test disc member  208  is aligned with the third guide member  207 , but is not constrained thereby. The upper surface  303  of the uppermost test disc member  208  is in contact with a lowermost surface of the first guide member  205 . The lowermost surface of the second guide member  206  is at the same level as the lowermost end of the first guide member  205 . However, the second guide member  206  coincides with part of the cutaway portion  302  of the first test disc member  208  at the orientation of the test disc member  208  shown in  FIG. 6 . As such, there is no contact between the second guide member  206  and the first test disc member  208  when the first test disc member is in this position. The test disc members  208  to  210  are biased in an upwards direction by bias means (not shown), which may be a spring. However, the test disc members  208  to  210  are prevented from moving upwards within the cartridge  106  by virtue of the contact between the upper surface  303  of the first test member  208  and the lowermost end of the first guide member  205 . 
         [0066]    At the position shown in  FIG. 6 , the distal end of the lancet  309  is not co-located with the aperture  105 . As such, the lancet  309  is in this position not operational. Put another way, the lancet  309  at this position is shielded by the hollow cylindrical part  203 , which constitutes part of the housing. 
         [0067]    From the position shown in  FIG. 6 , the shaft  204  is caused to rotate in a first direction, for example in a clockwise direction, by action of the drive wheel  201  and drive belt  202 . The drive dog  320  is engaged with the drive notch  307  in the hole  306  of the test disc member  208 , and so allows rotation of the shaft  204  to result in rotation of the test disc member  208 . Rotation brings the lancet  309  in front of the aperture  105 . As such, a skin-covered part of a user (hereafter the part will be referred to as a user&#39;s digit, for the sake of convenience) is lanced by the lancet  309 . This produces a puncture in the skin of the digit, through which blood can escape.  FIG. 9  shows the first test disc member  208  rotated to the position where the lancet  309  is operable to lance the user&#39;s digit. The shaft  204  is caused to rotate only by a predetermined amount, the maximum extent of travel of the lancet  309  is controlled. The penetration of the lancet  309  in the user&#39;s digit depends on a number of factors, as will be appreciated by the person skilled in the art. The amount of rotation, and thus the depth of penetration, may be definable by a user. 
         [0068]    Subsequently, the shaft  204  is controlled to rotate in an opposite direction, for example in an anticlockwise direction. This causes the lancet  309  to be removed from the user&#39;s digit, and for the disc edge  305  at the cutaway portion  302  to rub the user&#39;s digit as the test disc member  208  rotates. At a point in the rotation of the test disc member  208 , the lowermost part of the second guide member  206  ceases to coincide with the cutaway portion  302  and so is able to exert a reaction force on the upper surface  303  of the test disc member  208 . A short time thereafter, the lowermost part of the first guide member  205  becomes coincident with the cutaway portion  302 , and ceases to contact the upper surface  303  of the test disc member  208 . At this point, it is the second guide member  206  that prevents the first test disc member  208  moving upwards within the cartridge  206 . 
         [0069]    The test disc member  208  continues to rotate until the blood collection portion  315  is aligned with the aperture  105 . Here, rotation ceases. At this location, blood that has been caused to be expelled from the user&#39;s digit by the lancet  309  and by action of the disc edge  305  on the user&#39;s digit is caused to be drawn to the analyte measuring part  316  by capillary action. The blood and the enzyme then react. 
         [0070]    At a suitable time, the shaft  204  is caused to be rotated further in the opposite direction, for example in an anticlockwise direction. Here, the test disc member  208  is caused to be rotated from the position shown in  FIG. 10 , in which the blood collection portion  315  is coincident with the aperture  105 , to the position shown in  FIG. 11 . Here, the notch  301  is aligned with the second guide member  206 . Because at this location the first guide member  205  is coincident with the cutaway portion  302  of the test disc member  208 , neither of the first or second guide members  205 ,  206  prevents upwards movement of the first test disc member  208 . As such, the first to third disc members  208  to  210  are moved upwards by virtue of the bias means (not shown). 
         [0071]    When the first test disc member  208  moves upwards, between  FIGS. 11 and 12 , the drive dog  320  ceases to cooperate with the drive notch  307  of the hole  306  of the first test disc member  208 . Before the first test disc member  208  reaches the position shown in  FIG. 12 , a lower surface of the drive dog  320  contacts the upper surface  303  of the second test disc member  209 . This prevents further upward movement of the second test disc member  209 , and thus prevents further movement of the test disc member  210 . At this position, the shaft  204  is caused to be rotated by the drive wheel  201  and the drive belt  202  such that the drive dog  320  is coincident with the drive notch  307  of the second test disc member  209 . At this location, the second disc member  209  is able to move upwards on the shaft  204 , thereby engaging the drive dog  320  with the drive notch  307  of the second test disc member  209 . After the second test disc member  209  has moved upward by a distance equal to the height of the spacer member  308 , further upwards movement of the second test disc member  209  is prevented by contact between the first guide member  205  and the upper surface  303  of the second test disc member  209 . At this point, which is shown in  FIG. 12 , the second guide member  206  is located within the notch  301  of the first test disc member  208 . This prevents further rotation of the first test disc member  208  within the cartridge  106 . 
         [0072]    By virtue of movement up the cartridge  106  of the first to third test disc members  208  to  210 , the third guide member  207  ceases to be within the notch  301  of the second test disc member  209 . At this stage, the third guide member  207  does not prevent rotational movement of the second disc member  209 . 
         [0073]    At the position shown in  FIG. 12 , the second test disc member  209  is in exactly the same position as was the first test disc member  208  at the position shown in  FIG. 6 . Furthermore, the shaft  204 , and thus the drive dog  320 , has the same orientation. As such, the second test disc member  209  is able to be used to elicit a blood sample from a user and test the glucose level thereof in the same way as was the first test disc member  208 . 
         [0074]    By providing a stack of test disc members  208  to  210  within the cartridge  106  and by providing a suitable physical arrangement, a cartridge  106  can be used for multiple tests. When the cartridge  106  is new, the test disc members  208  to  210  are located in the bottom half of the cartridge  106 , with the uppermost test disc member being aligned with the aperture  105 . As test disc members are used, the stack of test disc members moves upwards in the cartridge. When the last test disc member is used, the cartridge can be said to be spent. At this stage, all of the test disc members are located in the uppermost portion of the cartridge  106 . 
         [0075]    It will be appreciated that the number of test disc members  208  to  210  that can be accommodated within the cartridge  106 , and thus the number of tests that can be provided by a cartridge  106 , is a factor of the height of the cartridge  106 , and the separation between corresponding parts (e.g. the upper surfaces) of adjacent test disc members  208  to  210 . A taller cartridge and/or a reduced separation of test disc members increases the number of tests that can be performed using a single cartridge  106 . 
         [0076]    Referring now to  FIGS. 13 to 18 , an arrangement in accordance with aspects of the invention is shown. Here, the arrangement and operation is as described above with reference to  FIGS. 5 to 12  unless otherwise stated. Reference numerals are retained from earlier described figures for like elements. 
         [0077]    As shown in  FIG. 13 , the hollow cylindrical housing part  203  is provided with the aperture  105  and the slit aperture  400 . The shaft  204  is supported centrally within the hollow cylindrical housing part  203  of the cartridge  106 . However, the diameter of the shaft is less than in  FIGS. 5 to 12 . 
         [0078]    A plunger arrangement  500  comprising a plunging arm  501  and a plunging head  502  is provided adjacent a plunging aperture (not shown) in the hollow cylindrical housing part  203 . The plunging aperture (not shown) is located next to the slit aperture  400 . The plunging aperture (not shown) is located directly opposite to the aperture  105 . The plunger aperture and the slit aperture  400  may be combined to form a single aperture. The plunger aperture is configured to allow the plunging head  502  to be forced by the plunging arm  501  to a position internal to the hollow cylindrical housing part  203 . 
         [0079]    Within the cartridge  106  are plural test disc members, one of which is shown as  505  in  FIG. 14 . 
         [0080]    A lancet  506  is provided extending from the disc edge  305  in the cutaway portion  302 . In particular, the lancet  506  extends in a radial direction with respect to the centre of the test disc member  505 . The lancet  506  extends from a fourth position  507 , which is near to the second position  313 . The fourth position  507  is further from the second position  313  than is the corresponding first position  312  in the arrangement described above with reference to  FIGS. 5 to 12 . However, because the lancet  506  is radial with respect to test disc member  505 , a distal end  506 A of the lancet  506 , i.e. the end that is furthest from the centre of the test disc member  505 , is at approximately the same position as the corresponding end of the lancet  309 . 
         [0081]    The majority of the test disc member  505  is substantially rigid. However, an annular centre portion  508  is comprised of an elastically deformable material. In particular, the annular centre position  508  is deformable in the presence of an externally applied force. This means that the test disc member  505  can be displaced relative to the shaft  204 , as will be described in more detail below. The material used to form the annular centre portion  508  may take any suitable form, and for instance may be a rubberised plastic. 
         [0082]    In  FIG. 15 , the hollow cylindrical housing part  203  is omitted from the figure. In  FIG. 15 , the test disc member  505  is shown as having been rotated to a position at which the lancet  506  is coincident with the aperture  105 . It can be seen that the plunging head  502  is aligned with the test disc member  505  such that movement of the plunger arrangement  500  along the longitudinal axis of the plunging arm  501  causes the plunging head to contact the test disc member  505  and apply force to it. Since the longitudinal axis of the plunging arm  501  is radial with respect to the shaft  204 , the force applied by the plunger arrangement is directed towards the shaft  204 . 
         [0083]    In  FIG. 16 , the arrangement is shown after a force has been applied to the plunger arrangement  500  so as to displace it by a predetermined amount. Here, the plunging head  502  has contacted the test disc member  505  on the opposite side of the test disc member to the lancet  506 . The annular centre portion  508  has become compressed on the side closest to the plunger arrangement  500  such as to allow the whole of the test disc member  505  to be displaced in the direction of the force supplied by the plunger arrangement  500 . The test disc member  505  remains horizontal by virtue of the spacer members  308 . 
         [0084]    Displacement of the test disc member  505  in the direction of the force supplied by the plunger arrangement  500  has resulted in displacement of the lancet  506  in a radial direction away from the shaft  204 . In this position, the lancet  506  penetrates the skin of the user&#39;s digit. Removal of the force by the plunger arrangement  500  allows the annular centre portion  508  to return to its original form, through elastic reformation. After the plunger arrangement  500  has been fully retracted, the arrangement again has the form shown in  FIG. 15 . Here, the test disc member  505  is in its original position and the lancet  506  is retracted from the user&#39;s digit. It will be appreciated that it is the elasticity of the annular centre portion  508  of the test disc member  505  that allows the test disc member  505  to return to this position once the force applied through the plunger arrangement  500  is removed. 
         [0085]    After removal of the force supplied by the plunger arrangement  500 , the test disc member  505  can be rotated by the drive wheel  201  and the drive belt  202  so as to provide milking of the user&#39;s digit and then collection of blood at the blood collection portion  315 , which position is shown in  FIG. 17 . After a measurement of blood glucose level is taken, the test disc member  505  is rotated further anticlockwise so that the second guide member  206  is aligned with the notch  301 , and thus the test disc member  505  is allowed to move upwards within the cartridge  106 . As a result, the test disc member  509  that is immediately below the first test disc member  505  also moves upwards within the cartridge  106  and is provided to be coincident with the aperture  105 , the slit aperture  400  and the plunger aperture (not shown). Subsequent application of a plunging force by the plunger arrangement  500  causes a lancet  506  of the second test disc member  509  to be forced out of the aperture  105 , as is shown in  FIG. 18 . The process can be repeated for other test disc members included in the cartridge  106 . 
         [0086]    An advantage of the arrangement shown in  FIGS. 13 to 18  is that a rotational arrangement can be used whilst allowing the lancet  506  to penetrate a user&#39;s skin in a longitudinal direction with respect to the lancet  506 . Another advantage is that puncture can occur at any desired location, for instance on the end of the user&#39;s digit, instead of puncturing occurring slightly on the side of the end of the digit. 
         [0087]    Another advantage is that the arrangement can allow the penetration depth of the lancet  506  to be easily predictable. 
         [0088]    Furthermore, it allows the penetration or puncturing depth to be adjustable. In particular, the adjustment of the penetration depth can be achieved by a mechanical arrangement that limits movement of the plunger arrangement towards the shaft  204 . Alternatively, it can be achieved in an electro-mechanical manner by measuring the location or displacement of some part of the mechanism and ceasing applying an energising voltage to a solenoid or other transducer that is used to affect movement of the plunger arrangement  500 . The penetration depth may be specified by a user. The depth may be specified by a user may be achieved through software or firmware control of rotation of the shaft  204 . The penetration depth may be defined by the user for example using one or more of the first, second and third inputs  101  to  103 . For instance, the first and second inputs  101 ,  102  may be increase and decrease respectively, with the third input  103  being a select or confirm input. The value defining the depth may be stored in memory. Penetration depth control is important to many users since lancet penetration usually is painful and since penetration depth control allows users some control over their experience. 
         [0089]    Reference will now be made to  FIGS. 19 to 21 , which illustrate connection of the analyte measuring part  316  to measurement circuitry (not shown). 
         [0090]    Referring firstly to  FIG. 19 , the hollow cylindrical housing part  203  is shown with the aperture  105  and the shaft  204  located as described above. A slit aperture  400  is provided in the hollow cylindrical housing part  203 . The slit aperture  400  is located at substantially the same height as the aperture  105 . However, the slit aperture  400  is located on a side of the hollow cylindrical housing part  203  that is substantially opposite the aperture  105 . 
         [0091]    The slit aperture  400  does not coincide with the elongate aperture  110  that is formed at the front side of the BGM  100 . As such, the slit aperture  400  is not visible when the cartridge  106  is in place within the BGM  100 . 
         [0092]      FIG. 20  is the same view as shown in  FIG. 19  although the hollow cylindrical housing part  203  is omitted. 
         [0093]    Adjacent to the slit aperture  400  is located a swing arm  401 . The swing arm  401  is rotatable about a spindle  402 , as shown in  FIG. 21 . The spindle  402  has an axis that is parallel to the axis of the shaft  204 . The axis of the spindle  402  is located above the drive belt  202 . A connecting arm  403  connects the spindle  402  to the swing arm  401 . In this example, the connecting arm  403  is connected to the swing arm  401  by a vertical connector  404 . The vertical connector  404  allows the spindle  402  on which the connecting arm  403  is mounted to be located at a different vertical position to the swing arm  401 . The spindle  402 , the connecting arm  403  and the vertical connector  404  are arranged such that when the connecting arm is rotated on the axis of the spindle  402  the swing arm  401  is moved towards the shaft. The movement of the swing arm  401  is substantially radial with respect to the shaft  204 . 
         [0094]    Mounted on the swing arm  401  are first to third electrical contact terminals  405 . Each includes a generally horizontal arm  405   a  and a depending contact head  405   b.  The electrical contact terminals  405  are made of a resilient conductive material, for instance metal. The depending contact heads  405   b  are angled at their ends furthest from the swing arm  401 . 
         [0095]    In one position, shown in  FIGS. 19 and 20 , the electrical contact terminals  405  are supported by the swing arm  401  such that the dependent contact heads  405   b  are located within the slit aperture  400  or alternatively outside of the hollow cylindrical housing part  203 . When the test disc member  505  is rotated such that the blood collection part  315  is coincident with the aperture  105 , as shown in  FIG. 20 , the contact pads  318  are coincident/aligned with the slit aperture  400 . As the test disc member  505  is held in this position, the connecting arm  403  is caused to rotate around the axis of the spindle  402  such that the swing arm  401  moves towards the shaft  204 . The arrangement is such that the depending contact heads  405   b  of the electrical contact terminals  405 , but not the horizontal arms  405   a,  come into contact with the contact pads  318  as the electrical contact terminals  405  move into the volume above the upper surface  303  of the test disc member  505 . The resilient properties of the electrical contact terminals  405  causes the electrical contact terminals to be forced against the contact pads  318 . As such, an electrical connection is provided between the horizontal arms  405   a  of the electrical contact terminals  405  and the analyte measuring part  316 . Electronic measuring means (not shown) connected to the electrical contact terminals  405  operate to pass a voltage through the contact terminals  405  and the analyte measuring part  316  and to take measurements of electrical parameters, from which a measurement of an analyte concentration level, for example a blood glucose level, can be determined. 
         [0096]    The connecting arm  403  is controlled to remain in a position shown in  FIG. 21  for a predetermined time or alternatively until it is detected that a blood glucose level measurement has been made, after which the connecting arm  403  is caused to rotate around the shaft  402  so as to remove the electrical contact terminals  405  from the position above the upper surface of the test disc member  505 . At this stage, the arrangement is as shown in  FIG. 20 . Once the electrical contact terminals  405  have been retracted, the test disc member  505  is rotated anticlockwise so as to allow the test disc members  505  to move upwards on the shaft  204 . 
         [0097]    It will be appreciated that the maximum permissible height dimension of the electrical contact terminals  405  is determined by the height of the spacer member  308 . A thicker spacer member allows larger electrical contact terminals  405  to be used. However, this is at the expense of an increase in separation between adjacent test disc members  505 , and thus a reduced capacity for the cartridge  106 . The use of electrical contact terminals  405  including a horizontal arm  405   a  and a depending contact head  405   b  allows the height dimension of the electrical contact terminals to be minimised whilst allowing good electrical contact between the electrical contact terminals and the contact pads  318  and also allowing the electrical contact terminals  405  to operate correctly over a sufficient number of cycles. 
         [0098]    The configuration of the test disc members  505  is such that operation results in milking of the puncture in the user&#39;s digit caused by the lancet  506 . In particular, the aperture  105  is configured such as to allow an amount of the flesh making up the end of the user&#39;s digit to be present within the internal volume of the cylindrical part  203  when the user presses the digit up against the aperture  105 . When the user applies force into the aperture  105  with the digit, the digit distorts and a bulbous part is provided within the internal diameter of the hollow cylindrical housing part  203 . The size of the bulbous part, and in particular the height of the bulbous part, depends on a number of factors, including the physical characteristics of the user&#39;s digit and the amount of force that the user applies, as well as the configuration of the aperture  105 . 
         [0099]    The aperture  105  is dimensioned such that in normal use (i.e. with a typical user applying a typical amount of force) a bulbous part of the user&#39;s digit extends into the internal volume of the hollow cylindrical housing part  203  to a depth of approximately 1 millimetre. The test disc members  505  are configured to have a cutaway portion  302  that is shaped such that when the lancet  506  is at a position at which it can lance the user&#39;s digit, the disc edge  305  is not in contact with the user&#39;s digit (i.e. the separation between the disc edge  305  and the aperture  105  is greater than 1 mm). This part of the cutaway portion  302  can be termed a first milking portion. At this position, the pressure exerted by the user results in the fluid pressure within the bulbous part of their digit being slightly greater than normal pressure. The increased pressure results from the force the user applies to their digit. This pressure encourages bleeding of the puncture that is caused by the lancet  506 . Advantageously, the arrangement of the relevant features is such that the lancet  506  penetrates the user&#39;s digit to a depth of between 0.4 and 0.7 millimetres. 
         [0100]    As the test disc member  505  rotates anticlockwise after lancing, the end of the bulbous part of the user&#39;s digit comes into contact with the disc edge  305  at a position approximately one-third to two-fifths of the way along the cut out portion  203 . This part can be termed the second milking portion. The test disc member  208  to  210 ,  505 ,  600  has a substantially constant radius for the second milking portion, which extends to a position approximately two-thirds or four-fifths of the way along the cutaway portion  302 . For the time at which the second milking portion is coincident with the bulbous part of the user&#39;s digit as the test disc member  208  to  210 ,  505  rotates, the internal pressure of the bulbous part of the user&#39;s digit is increased compared to the time at which the user&#39;s digit was in contact with the lancet  309 . Furthermore, as the disc edge  305  moves into contact with and over the bulbous part of the digit, blood under the skin is caused to be pushed towards the puncture caused by the lancet. 
         [0101]    Between the second milking part and the location of the blood collection part  315 , the radius of the test disc member  505  is reduced, or put another way has a lower value. This portion can be termed a third milking portion. As such, after the second milking portion and before the user&#39;s digit contacts the blood collection part  315 , the pressure applied to the bulbous part of the user&#39;s digit by the disc edge  305  is reduced compared to the pressure applied at the second milking portion. Advantageously, the radius of the test disc member  505  at the third milking portion is selected such that the bulbous part of the user&#39;s digit does not contact the disc edge  305  (i.e. the separation between the disc edge  305  and the aperture  105  is greater than 1 mm). Whilst the third milking portion is coincident with the user&#39;s digit as the test disc member  505  rotates, blood is free to exit the puncture made by the lancet  506 . As the test disc member  505  continues to rotate, the disc edge  305  again contacts the bulbous part of the user&#39;s digit at a location just before the blood collection portion  315 . This again increases the internal pressure within the bulbous part of the user&#39;s digit. This encourages the movement of blood towards the analyte measuring part  316 . The separation between the disc edge  305  at the location of the blood collection portion  315  and the aperture  105  is approximately 0.5 mm. 
         [0102]    The configuration of the test disc members  505  thus encourages milking of a sample of blood from the user&#39;s digit. The sequence is as follows: Firstly, lancing by the lancet  506  with a relatively low pressure (caused by no contact with the disc edge  305  and the user&#39;s digit), followed by a period for which relatively low amount of pressure, as well as a rubbing movement, is provided by the second milking portion to the user&#39;s digit, followed by a period for which little or no pressure is provided by the disc edge  305  against the user&#39;s digit, followed by a relatively high pressure provided by the disc edge  305  against the user&#39;s digit just before and at the blood collection part  315 . 
         [0103]    Operation of the blood glucose meter  100  will now be described with reference to the flowchart of  FIG. 22 . 
         [0104]    Operation starts at step T 1 . At step T 2 , the user locates their digit in the aperture  105 . As mentioned above, the user forces their digit into the aperture  105  with a pressure or force that is suitable to allow lancing and blood collection. At step T 3 , the user initiates blood glucose measurement. This involves the user pressing one of the inputs  101  to  103 . This is detected by the microprocessor  212  by way of the keys interface  215 . The software/firmware stored in the ROM  214  uses the key input to call a function or to execute a software module. The software/firmware stored in the ROM  214  then causes the microprocessor  212  to issue a command to a motor attached to the drive wheel  201  through the motor interface  217  to rotate the shaft  204  in a first direction, for example in a clockwise direction. The software/firmware controls the extent of the rotation. 
         [0105]    Following step T 3 , the microprocessor  212 , under control of the software/firmware stored in the ROM  214 , causes the shaft  204  to be rotated by a motor through the motor interface  217  and to cease rotation once the lancet  508  is aligned with the aperture  105 , and thus is aligned with the user&#39;s digit, at step T 4 A. At step T 4 B, the microprocessor  212 , under control of the software/firmware stored in the ROM  214 , causes actuation of the plunger arrangement  500 , through the motor interface  217 . The control of the actuation of the plunger is such as to limit the extent of movement of the lancet  508  to a predetermined extent. The predetermined extent is set by a user through operation of the keys  102 ,  103  prior to the blood glucose measurement. In effect, the user can use the keys  102 ,  103  to set a lancing depth, which is stored in a suitable way in the ROM  214  by action of the microprocessor  212 , operating under control of the software/firmware stored in the ROM  214 . 
         [0106]    When the maximum extent of plunger actuation has been reached at step T 4 B, at step T 4 C the plunger arrangement  500  is deactuated by the microprocessor  212 , under control of the software/firmware stored in the ROM  214 , and lancing ceases. At this step, the test disc member returns to its original position by action of the elasticity of the annular centre portion  508  of the test disc member  508 . 
         [0107]    Although in the figures, an in particular in  FIG. 7 , three conductive tracks  317  and three conductive pads  318  are shown, it will be appreciated that this is merely illustrative. There may instead be only two conductive tracks  317  and two conductive pads  318 , or alternatively there may be more than three conductive tracks and conductive pads. 
         [0108]    The software/firmware stored in the ROM  214  then causes the microprocessor  212  to control the motor to rotate the shaft  204  in the opposite direction, at step T 5 . As the test disc member rotates anticlockwise, milking occurs at step T 6 . Firstly, at step T 6 A, there is no pressure applied by the test disc member on the digit. At step T 6 B, there is a medium amount of pressure on the digit. At step T 6 C, there is low or no pressure applied by the test disc member on the digit. At this point, the digit coincides with the part of the test disc member that is immediately before the blood collection part  315 . 
         [0109]    At step T 7 , the software/firmware causes the microprocessor  212  to control the motor to cease rotation when the shaft  214  is such that the blood collection member  315  is coincident with the aperture  105 , and thus the user&#39;s digit. At step T 8 , the software/firmware controls a motor such as to cause the swing arm  401  to be rotated towards the shaft  204 . The software/firmware stored in the ROM  214  is such that the microprocessor  212  causes only the required amount of travel of the swing arm  401 . At this point, the analyte interface circuit  219  is coupled directly to the blood analyte measuring part  316 , which by action of the blood collection part  315  has been provided with blood from the user&#39;s digit. At step T 9 , analyte measurement is performed. This involves the analyte interface circuit  219  providing voltages to the electrical connection contacts  318 , and thus to the blood analyte measuring part  316 , and measuring parameters of resulting signals. The measured parameters, particularly voltage parameters, are used by the software/firmware stored in the ROM  214 , as executed by the processor  212 , to calculate a blood glucose measurement level of the user. The blood glucose measurement is then caused by the software/firmware to be displayed on the display  104  through action of the microprocessor  212  on the display drive  216 . At step T 10 , the swing arm is caused to be removed by action of the microprocessor  212 , under control of the software stored in the ROM  214 , the motor interface  217  and the motor (not shown). 
         [0110]    At step T 11 , the software/firmware results in the microprocessor  212  controlling the drive disc  201  to rotate in the opposite direction. Rotation continues until the notch  301  on the test disc member is coincident with the guide  206 . At step T 12 , the test disc member rises up the cartridge  106 . In the case where biasing of the test discs up the cartridge  106  is provided by a bias means, for instance a spring, step T 12  requires no action on part of the software/firmware and microprocessor  212 , although there may be a pause before the next step. In embodiments where movement of the test disc members along the shaft  204  occurs through driving action, step T 12  involves the microprocessor  212 , under control of the software/firmware stored in the ROM  214 , controlling a motor through the motor interface  217 . Subsequently, at step T 13 , the microprocessor  212 , under control of the software/firmware stored in the ROM  214 , causes the shaft  204  to rotate again in the first direction and to cease rotating when the drive dog  320  engages with the drive slot  307  of the next test disc member in the cartridge  106 . At this stage, the test disc members rise up the cartridge  106  slightly. 
         [0111]    The operation ends at step T 14 . 
         [0112]    Various modifications and alternative features can be used in connection with the above-described embodiments. Some alternatives now follow. 
         [0113]    Instead of the blood collection part  315  being located next to the third position  314 , i.e. bounding only the part of the disc edge  305  that is purely circumferential, the blood collection part could instead be located on the disc edge  305  at the junction between the cutaway portion  302  and the circumferential portion. The blood collection  315  part in this instance may extend for between 0.5 mm and 2 mm along the disc edge  305  at the cutaway portion  302 . The blood collection  315  part in this instance may also extend for between 0.5 mm and 2 mm along the disc edge  305  at the circumferential part. 
         [0114]    Alternatively or additionally, the analyte measuring part  316  may be sandwiched between two layers of wicking material, the wicking material causing the blood to be drawn through the analyte measuring part  316 . 
         [0115]    Although in the above the shaft  204  is said to be driven by a drive wheel  201  that is coupled to the shaft  204  by a drive belt  202 , the drive may instead be direct (i.e. the drive mechanism is coupled directly to the shaft  204 ), or connection may be made by a notched belt, a vee belt, or by a direct gear mechanism. Instead of an electric motor, a clockwork drive could be used. A clockwork drive mechanism has a number of advantages, particularly where access to batteries or battery chargers or electricity supplies are limited. In the embodiments in which a clockwork mechanism is used, the user can be sure that the BGM  100  will not cease operating because of drained batteries. A clockwork mechanism may be particularly suited to developing countries and emerging markets. 
         [0116]    In embodiments in which an electrical motor is used to drive the shaft  204 , preferably control is exerted over the motor by software. In this way, the speed of rotation can easily be controlled. Additionally, the extent of rotation can more easily be controlled. The motor may be a stepper motor. 
         [0117]    Alternatively, a mechanical drive arrangement may be present, for instance using a lever or other device for manual actuation. A suitable mechanism may be one similar to those previously used in SLR cameras. 
         [0118]    The swing arm  401  may be actuated in any suitable way. For instance, it may be driven by the same motor or mechanism as the shaft  204 . Alternatively, it may be driven by a separate motor. In either case, the rotation of the swing arm  404  may be affected by a cam mechanism, or by a pin and slot (track path) mechanism. In the event of an electric motor being used, the motor preferably is software driven. The motor preferably is a stepper motor. 
         [0119]    The mechanical arrangement may include a mechanism by which a bias means, for instance a mechanical compression spring, is biased and then released in order to push the electrical contact terminals  405  into place. The terminals  405  can then be retracted by the swing arm  401  using a rotating motion. The overall mechanism can be termed a latch type trigger mechanism. 
         [0120]    Instead of a swing arm  401  being used to rotate the electrical contact terminals  405  into place, the contact pads  318  may instead be located on the disc edge  305 , allowing the use of fixed electrical contact terminals  405 . The electrical contact terminals may include a brush or other deformable feature such that the test disc members  208  to  210 ,  505 ,  600  can move whilst in contact with the electrical contact terminals without damage occurring to any of the components. Similar arrangements are used in brushed DC motors. In this case the electrical contact terminals  405  could be flexible finger contacts that rest on the periphery of the test disc members  208  to  210 ,  505 ,  600  in order to contact the contact pads  318 . 
         [0121]    Alternatively, instead of a swing arm  401 , a mechanism may be used to affect longitudinal movement of the electrical contact terminals  405  into place to contact the contact pads  318 . 
         [0122]    The conductive tracks  317  and the contact pads  318  may be formed by leadframe. Alternatively, overmoulding may be used. Alternatively, printed circuit board (PCB) printing may be used. 
         [0123]    Optionally, each of the test disc members  209 ,  210 ,  505 ,  600  is separated from adjacent test disc members by a membrane (not shown in the drawings). In this case, the membrane preferably fits closely to the internal surface of the hollow cylindrical housing part  203 . An effect of the membrane is to reduce the possibility of disc cross-contamination. Use of a membrane may allow the test disc members  208  to  210 ,  505 ,  600  to have a reduced separation than would be the case without the use of a membrane. 
         [0124]    In the above, the test disc members  505  are said to be biased upwards by a bias means, for instance a compression spring. Alternative mechanisms for moving the test disc members  505  up the cartridge may be used. For instance, a threaded lifting cam may be provided on the shaft  204  or alternatively on the interior surface of the hollow cylindrical housing part  203 . Alternatively, the test disc members  505  may remain stationary, with the aperture  105  and the drive dog  320  instead being moved along the axis of the cartridge  106 . Movement of the aperture  105  may be achieved by the use of a sliding door in an elongated slot. Movement of the door allows a different strip to be revealed at the aperture  105 . 
         [0125]    Instead of the blood collection portion  315  wicking blood towards the analyte measuring part  316 , blood may be communicated to the analyte measuring part  316  instead through gravity. 
         [0126]    Additionally, the test disc members  505  may include a disinfecting or cleaning portion that contacts the digit before lancing. This can reduce risk of infection of the wound and also can increase accuracy in particular by removing any glucose from the skin (as may occur after eating fruit etc.). 
         [0127]    Additionally or alternatively, the test disc members  505  may include a cleaning portion that is arranged to contact the digit subsequent to the blood collection part  305 . This can remove additional blood from the finger, and may also serve to assist closure of the puncture.