Abstract:
A lancing device includes a housing for containing a lancet. A lancet driver couples with and moves the lancet within the housing. A skin interface cap has an opening defined therein to expose at least part of the lancet when moved by the driver. A sliding frame is coupled to the housing and to the skin interface cap. The frame being adjustable relative to the housing for accordingly adjusting said cap relative to the housing, whereby an extent to which the lancet is exposed through the opening is adjustable by adjusting the sliding frame.

Description:
BACKGROUND 
       [0001]    Measurements of blood glucose levels typically involve a blood expression process for acquiring a sample of blood or other body fluid for analysis. To acquire a blood sample, for example, the skin may be punctured to a pre-determined depth using a needle or a lancet to create a small wound. Creation of a shallower wound is normally less painful than creation of a deeper wound. However, deeper wounds normally produce more blood than shallower wounds. Only if there is a sufficient amount of blood available will the measurement be possible and/or reliable depending on the type of assay being performed and on the assay equipment being used. Individuals differ in the amount of blood that is made available upon creation of a certain depth or extent of wound. Various individuals have different blood circulation, skin texture, etc., and would like to adjust the lancing depth to a comfortable yet useful value for them. It is desired to be able to adjust the lancing depth to an optimum value that is sufficient for producing enough blood for performing analysis and that is minimally painful. 
         [0002]    When a lancing device, including an in integrated blood glucose monitoring system, is used, e.g., as described in U.S. application Ser. Nos. 11/535,985 and 11/585,986, it is also desired to be able to adjust the lancing depth adjustment. The lancing depth adjustment is more challenging for implementing in integrated blood glucose systems though, because such systems are already very complicated even without providing an additional lancing depth adjustment capability. 
         [0003]    Some conventional stand-alone lancing devices include lancing depth adjustment capability. These are generally provided in one of two ways. The first way includes lancing depth adjustment which forms a part of the lancing mechanism. The second includes a rotatable, telescopic cap on the housing of the lancing device. Both of these approaches have significant disadvantages when used in integrated blood glucose monitoring systems. The first approach involves an additional complication of an already complex lancing-advance mechanism. The rotatable, telescopic cap involves incorporation of quite complicated telescopic mechanism on a compact blood expression cap. 
       SUMMARY OF THE INVENTION 
       [0004]    It is recognized by the present inventor that it would be advantageous to have a depth adjustment mechanism that is separate from a lancing mechanism, particularly in an integrated lancing and glucose sensing device, e.g., instead forming part of the external housing of the integrated device with the depth adjustment mechanism. Embodiments are described below that allow lancing depth adjustment via moving a part of the external housing to a predetermined distance with respect to the lancing mechanism. 
         [0005]    Lancing devices are provided including a lancet for piercing skin and exposing blood to perform an assay. Embodiments include a lancet driver coupled with and moving a lancet within a housing. A skin interface cap has an opening defined therein to expose at least part of the lancet when moved by the driver. A sliding frame is coupled to the housing and to the skin interface cap. The frame is adjustable relative to the housing for accordingly adjusting the cap relative to the housing, whereby an extent to which the lancet is exposed through the opening is adjustable by adjusting the sliding frame. 
         [0006]    Embodiments also include a housing for containing a lancet. A lancet driver couples with and moves the lancet within the housing. A sliding skin interface cap couples to the housing and has an opening defined therein to expose at least part of the lancet when moved by the driver. The sliding skin interface cap is adjustable relative to the housing for accordingly adjusting the opening relative to the housing, whereby an extent to which the lancet is exposed through the opening is adjustable by adjusting the sliding skin interface cap. 
         [0007]    With regard to either of these lancing device embodiments or alternative modification thereof, the skin interface cap may be coupled at a hinge to the housing, whereby the skin interface cap pivots around the hinge when the sliding frame is adjusted relative to the housing. A depth adjustment knob may be coupled to the sliding frame or sliding skin interface cap for controlling the adjusting of the sliding frame or interface cap. 
         [0008]    In certain embodiments, a glucose sensor and/or meter may also be disposed within the housing providing an integrated system for performing the assay upon application of blood to the sensor. The lancet driver may be configured to couple with the sensor such that upon retraction of the lancet, the lancet driver moves the sensor through the opening to contact and receive at least a portion of the blood. 
         [0009]    Embodiments may also include a pressure sensor may be provided for triggering the lancet driver to move the lancet through the opening when a predetermined pressure is applied to the skin interface cap and/or for permitting lancing upon activation of a switch when a predetermined pressure is applied to the skin interface cap. 
         [0010]    The cap may be shaped to promote blood expression at the opening. 
         [0011]    Methods of lancing skin and exposing blood to perform an assay are also provided. In certain embodiments, a lancet penetration depth is adjusted by sliding a skin interface cap relative to a housing and/or selected by adjusting a sliding frame relative to the housing, and thereby moving the opening relative to a lancet or lancet driver or both. The lancet is coupled to and moved by the lancet driver. At least part of the lancet is exposed through the opening in the skin interface cap to pierce skin that is provided at the opening at a depth selected by the adjusting to the skin interface cap. 
         [0012]    The methods may further include promoting expression of blood at the opening upon compression of the skin to the skin interface cap over the opening. 
         [0013]    The adjusting of the lancing penetration depth by sliding the skin interface cap may include rotating a depth adjustment knob, or the like. 
         [0014]    The methods may include rotating a depth adjustment knob for controlling the sliding of the skin interface cap. 
         [0015]    The methods may also include retracting the lancet, coupling a sensor with the lancet driver, and moving the sensor through the opening by moving the lancet driver so that the sensor contacts and receives at least a portion of the blood. 
         [0016]    The methods may include sensing a pressure applied to the skin interface cap and triggering the lancet driver to move the lancet through the opening, permitting lancing by activation of a switch and/or otherwise permitting lancing when a predetermined pressure is applied. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1A  schematically illustrates an external view of an integrated lancing and glucose monitoring device having lancing depth adjustment in accordance with a first embodiment, wherein the lancing depth is adjusted to a deepest position with the skin interface cap in contact with the fixed portion of the external housing. 
           [0018]      FIG. 1B  schematically illustrates an internal cross-sectional view of the device of  FIG. 1A  including a sliding frame for adjusting lancing depth by moving a skin interface cap relative to both a final most-exposed lancet position and the fixed portion of the external housing. 
           [0019]      FIG. 1C  schematically illustrates another external view of the device of  FIG. 1A , wherein the lancing depth has been adjusted to a shallower depth by moving the cap away from the fixed portion of the housing, such that a small portion of the sliding frame is now visible from the outside. 
           [0020]      FIG. 2A  schematically illustrates an external view of an integrated lancing and glucose monitoring device having lancing depth adjustment in accordance with a second embodiment. 
           [0021]      FIGS. 2B-2C  include cross-section internal views of the device of  FIG. 2A , particularly illustrating selected internal components. 
           [0022]      FIG. 3  illustrates a skin interface surface of a blood expression cap in accordance with certain embodiments. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0023]    Lancing depth-adjustment features are provided for a lancing device and/or a fully (or partially) integrated blood glucose monitor that includes a lancing device and a meter for measuring a glucose level in a bodily fluid and/or otherwise determining a blood glucose level of a user. The depth adjustment is achieved by moving a surface of the fully integrated meter or lancing device to a pre-determined distance with respect to the lancing mechanism. The lancing mechanism is not affected with regard to its position or motion within the housing of the monitor. Instead, the position of a skin interface cap is adjusted relative to the housing and lancing mechanism, thereby adjusting the position of the skin of the user relative to the position of maximum exposure of the lancet out of the housing. That is, depth adjustment features are provided at the external housing of the lancing device or integrated system. 
         [0024]    Embodiments of the skin interface caps include a blood expression cap for optimizing the obtaining of blood at a wound created by an incision formed by a lancing mechanism penetrating the skin of the user. The blood expression cap is designed to facilitate the expression of blood at the wound based on its contour or other physical design feature. The described design is mechanically robust and allows the application of a substantial load to the cap during the blood expression process. Also, the blood expression cap can be easily replaced or removed for cleaning purposes. 
         [0025]    The penetration depth of the lancet into the skin tissue is adjusted by moving a feature on the external housing of the lancing device or the meter.  FIG. 1A  schematically illustrates an example in accordance with one of several possible embodiments of the moving lancing depth-adjustment mechanism.  FIG. 1A  shows a lancing device or integrated lancing and blood glucose measurement system including a housing  1  containing one or more lancets and a lancet driver. Several lancets or striplets each including a lancet and a sensor may be provided in a cartridge such as described in the priority applications incorporated by reference herein. 
         [0026]    A skin interface cap  4  (“ 4 ” seems to be pointing to the end and not a “cap”) is in this case a blood expression cap  4  is mounted to the housing  1  at a hinge  2 . Movement of the cap  4  is facilitated in the example of  FIG. 1A  by a depth adjustment knob  8 . A sliding frame (not shown in  FIG. 1A , but see  FIGS. 1B-1C ) contacts the blood expression cap  4  opposite the hinge  2  causing the cap  4  to rotate about the hinge by moving the sliding frame up or down. This effectively moves the skin interface portion  14  of the cap  4  relative to the rest of the housing  1  (see, e.g., United States published patent application no. 2006/0089566, which is hereby incorporated by reference. As the lancet is configured to protrude from the skin interface portion  14  of the cap  4  during a lancing process to a maximum protrusion position relative to the housing  1 , upward adjustment (with respect to the illustration of  FIG. 1A ) of the portion  14  will result in a shallower wound and downward adjustment of the portion  14  will result in a deeper wound. Referring briefly to  FIG. 3 , the skin interface portion  14  may include a contoured section  301 . The skin interface portion  14  may include a single contoured section  301 , or may have multiple fingers  15  as in the embodiment illustrated at  FIG. 1A . In addition, a slit  310  may be included which intersects an otherwise circular or elliptical opening  320 , wherein the slit  310  permits test strips to protrude through the opening  320 . It is noted that any of the embodiments described herein may include a contoured section  301 , or a flat skin interface  14 ,  22 , and the skin interface  14 ,  22  may include multiple fingers ( FIG. 1A ) or a single continuous section ( FIGS. 2A and 3 ). 
         [0027]    The mechanism illustrated at  FIG. 1A  uses the blood expression cap  4  which pivots around the hinge  2  located on the meter housing  1 . Another side of the blood expression cap  4 , where the skin interface portion  14  is located, is coupled to the sliding frame (see  FIGS. 1B-1C ) which moves internally within and relative to the fixed housing  1 . 
         [0028]      FIG. 1B  is a cross-sectional internal view of the device of  FIG. 1A . The fixed housing  1 , hinge  2 , blood expression cap  4  or skin interface cap  4  including contact portion  14  and depth adjustment knob  8  are also shown in  FIG. 1A . The sliding frame  16  is not visible from the outside in  FIG. 1A . The sliding frame  16  is, however, partially visible in the external view of  FIG. 1C . The reason is that the depth adjustment is set at the deepest penetration depth in  FIG. 1A , which is when the skin interface cap  14  is flush in contact with the fixed frame  1 . The depth adjustment is set to a shallower depth in  FIG. 1C , wherein the skin interface cap  4  has been moved away from the fixed frame  1  at the skin contact portion  14  through the action of the sliding frame  16 . Because of the movement away from the fixed housing  1  of the portion  14 , the sliding frame  16  is partially visible from the outside of the housing, as indicated in  FIG. 1C . 
         [0029]    When the sliding frame  6  is moved up or down, the skin interface portion  14  of the blood-expression cap  4  is correspondingly moved up or down as well. However, another end of the blood expression cap  4  is attached to the hinge  2  and does not move. Therefore, the cap  4  rotates around the axis of the hinge  2  as a result of the movement of the sliding frame  6  as controlled by the depth adjustment knob  8 . This rotating motion tilts the cap  4  and raises or lowers the skin-interfacing portion  14  with respect to the lancing mechanism contained within the housing  1 . 
         [0030]    It is recognized in this embodiment that when the cap  4  is rotated, this will produce a small angular change between the normal to the skin interface portion  14  and the direction in which the moving lancet is pointed. That is, the angle with respect to the lancing mechanism between the skin-interfacing surface  14  of the blood expression cap  4  and the lancing direction will change, but such distance with respect to the lancing mechanism will be low as long as the hinge is located away from the lancing axis as illustrated at  FIG. 1A , because the adjustments in depth are sufficiently small. 
         [0031]    Another embodiment is illustrated schematically at  FIGS. 2A-2C . Referring to  FIG. 2A , the housing  21  of the lancing device or integrated lancing device and blood glucose monitor contains one or more lancets or striplets, a lancing driver, and perhaps glucose measurement electronics. In certain embodiments, a blood expression cap  22  includes a skin interface surface  30  that is shaped to facilitate the expression of blood and is coupled with a sliding frame (not shown in  FIGS. 2A-2B , but see  FIG. 2C  or  FIGS. 1B-1C ) that is adjustable relative to fixed portion of the housing  21  and the lancing driver (also not shown) by knob  26 . The position of maximum exposure of the lancet relative to the fixed housing is fixed, and so the lancing depth is adjustable by moving the skin interface surface  22  relative to the fixed housing  21 . The cap  22  in this case includes only the end portion appearing as an oval shape in  FIG. 2 . The top  28  of the housing  21  does not move relative to the rest of the housing  21  when the skin interface cap  22  is moved in this embodiment. 
         [0032]      FIGS. 2B-2C  illustrate features of the depth adjustment mechanism that are internal to the housing  21  of the device shown in an external view in  FIG. 2A . Referring specifically to  FIG. 2C , the depth adjustment knob  26  is a cam  26  having a cam path  34  defined in it. A cam follower  36  includes a cam extension (not shown) which fits in the cam path  34 . Rotation of the know  26  causes the cam follower  36  to move within the cam path  34  such that the cam follower moves relative to the substantial portion of the housing  21 . Although not shown, a lancet driver remains fixed in its position relative to the housing  21  when the depth adjustment mechanism is manipulated. However, the blood expression cap  22  moves up and down with the movement of the follower  36 , as a platform portion  38  of the cam follower  36  is coupled to, is in contact with, or is otherwise bound to follow the movement of the platform  38 . 
         [0033]    The embodiment of  FIGS. 2A-2C  uses a blood expression cap  22  which is, in certain embodiments, coupled directly to the sliding frame  24  which moves along and relative to the housing  21 . The position of the sliding frame  24  is regulated by the knob  26  which is coupled to the meter housing  21  for adjusting lancing depth. 
         [0034]    When the sliding frame  24  is moved up or down, one end of the blood-expression cap  22  is correspondingly moved up or down as well relative to the fixed housing  21  and a maximally-exposed position of the lancet when moved by the lancet driver (not shown). This motion moves the cap  22  and raises or lowers the skin contact surface  30  of the blood expression cap  22  with respect to the lancing mechanism. 
         [0035]    The sliding frame  24  of either of the second embodiment provides stable adjustability of the skin interface cap  22 , even though the cap  22  is not stabilized to the housing  21  at a hinge such as in the first embodiment. The sliding frame  24  contacts the cap  22  either at multiple points around the cap  22  or continuously for a sufficient extent that the cap  22  remains stable and does not wobble even when the cap  22  adjusted for shallow lancing depths away from the fixed housing. The cap  22  may have one or more legs that slide each in a channel provided in the fixed housing  21  to provide stability to the cap  22  by restricting the ability of the leg to rock due to its constraint within the channel. 
         [0036]    Certain embodiments can be practiced with either a simple lancing device or a completely integrated blood glucose meter. Different embodiments may be used to change the lancing depth to express blood from fingers, forearm, and alternative sites for blood glucose measurements, and/or on other analyte measurement applications. 
         [0037]    The present invention is not limited to the embodiments described above herein, which may be amended or modified without departing from the scope of the present invention as set forth in the appended claims, and structural and functional equivalents thereof. 
         [0038]    In methods that may be performed according to the embodiments herein and that may have been described above and/or claimed below, the operations have been described in selected typographical sequences. However, the sequences have been selected and so ordered for typographical convenience and are not intended to imply any particular order for performing the operations. 
         [0039]    In addition, all references cited above herein, in addition to the background, summary of the invention and brief description of the drawings sections, and the drawings, are all hereby incorporated by reference into the detailed description of the embodiments as disclosing alternative embodiments and components.