System for withdrawing blood

p0001The present invention relates to a system for withdrawing body fluid from a body part, in particular the finger pad, by producing a small puncture wound.

p0002In the field of clinical diagnosis, it is necessary, samples of body fluids, especially blood tests to win in order to prove it can ingredients. If a larger amount of blood required, this will be taken as a rule with a syringe or the like, to which a blood vessel is deliberately punctured. However, the present invention is in an area where only sample quantities in the region are less ul or less necessary to determine analytical parameters. Such an approach is particularly widely used for measurement of blood glucose levels, but they are also found, for example, application to coagulation parameters, triglycerides, HBA 1c or lactate to determine. In the field of diabetes, it has prevailed that diabetics perform their own monitoring of blood sugar levels (so-called. Home monitoring). This is necessary to set a blood sugar level through targeted doses of insulin, which is in the normal range. Device a diabetic If the initial blood sugar (hypoglycaemia) as this may result in a loss of consciousness and even death of a patient to be. Does the patient on the other hand too high blood sugar levels, so it attracts serious sequelae such blindness and gangrene by themselves. For required to measure the blood glucose level blood have small, handy Blood testing equipment, so-called. Lancing devices, naturalized, which can be operated by the user, hospital and caregiver easily and reliably. Since recently, systems for the extraction of interstitial fluid are known in principle with the corresponding analysis can be performed.

p0003A in this field strengthens abzeichnendes problem is the contamination and injury from used lancets. Many of the commercially available devices, the lancet is removed or ejected after the sting operation. The in such a case exposed needle of the lancet can lead to injuries which may attract infections. In some countries there are therefore already aspirations, blood collection systems in which the needle tip is freely accessible after use, to prohibit.

p0004In documents of the prior art, various variants have been described by blood collection systems in which the needle is protected after the sting operation. The document<patcit id="pcit0001" dnum="US5314442A"><text>US 5,314,442</text></patcit> describes a cap in which a lancet is disposed. To perform a puncture operation, the lancet is by a plunger or the like. Displaced within the cap so that the needle passes through an opening to the outside. After engraving the lancet is retracted back inside the cap and flexible elements on the lancet ensure that the lancet needle without the action of the plunger can no longer escape. In principle, similar systems are in<patcit id="pcit0002" dnum="US4990154A"><text>US Patents 4,990,154</text></patcit> and <patcit id="pcit0003" dnum="US5074872A"><text>5,074,872</text></patcit>And the international <patcit id="pcit0004" dnum="WO0002482A"><text>WO 00/02482 application</text></patcit> described. Another system, in which the withdrawal of a lancet is carried in a cap by a built-in spring, is in the document<patcit id="pcit0005" dnum="DE19855465"><text>DE 198 55 465</text></patcit> described. While the documents referred to already solve the problem of contamination or injury to the user, so a coupling of the drive mechanism is achieved to the lancet only by an interference fit. Here, the insertion depth of the needle is limited by a stop. However, it has been found that the impingement of the lancet leads to the stop of the needle to vibrations, which increase the pain during lancing. For details on this issue is in<patcit id="pcit0006" dnum="EP0565970A"><text>EP 0565970</text></patcit> described.

p0005The object of the present invention to provide a method for withdrawing body fluid, on the one hand avoids contamination or infection by used lancets and other, allowing the user a very painful poor grooving. Another object was to simplify the systems of the prior art to make more cost-effective and in particular to propose a concept that can be reduced. The latter point is particularly important to provide a system, which operates with a magazine, lancets and allows the user a change to an unused lancet, without having to make here too complicated handling steps.

p0006The above objects are achieved by embodiments of systems for withdrawing body fluid, having a drive unit having a plunger that is moved to carry out a lancing process from a rest position into a lancing position. Furthermore, the systems include a lancing unit in which a lancet is located with a needle which is arranged in the rest position of the plunger within the lancing unit and is displaced by the plunger when moved to the lancing position such that the needle at least partially through an outlet opening emerges from the lancing unit. An essential feature of the system is that the plunger and lancet to carry out the lancing process are coupled together by positive engagement.

p0007For a form fit in the context of this invention is characteristic in that it has lifted a coupling of the lancet and driving plunger by means of a low expenditure of energy is possible. There are two principal variants to achieve a form fit. In the first variant is followed for coupling of the lancet and plunger drive a mold in such a manner that a retaining element is enclosed. The closing end form is referred to in the present invention as a holding device. the holding device is located on the lancet, so has the plunger drive a holding element, is located on the other hand, the holding device on the drive ram, as the holding element on the lancet is disposed. The<figref idrefs="f0001">figures 1</figref> and <figref idrefs="f0002">2</figref> show practical embodiments. Preferably, this variant of the form fit is achieved by a transverse movement of retaining elements of a (first opened) holding device is achieved by a longitudinal movement in the puncturing direction, which in this case close to a holding area. Preferably on closing of the holding device wid the retaining element (at least partially) engaged behind, so that the lancet during the retraction of the drive ram - is taken - at least until the eventual opening of the holding device. Furthermore it is preferred if the holding device and holding area are geometrically matched to one another such that after a successful form fit no or only a small tolerance is toward the pricking movement and the movement of the drive ram is implemented both in the puncture direction and in the opposite direction without play in a movement of the lancet , This can be achieved by adjusting the longitudinal extension of the chamber in the closed Haltevrrichtung coincides with the longitudinal extent of the holding area, or is only slightly larger (see<figref idrefs="f0001">figure 1</figref>). In another embodiment of this variant, a recess in the holding area and holding elements of the holding device in their longitudinal extension are coordinated so that a transport in the puncture direction is substantially free of play (see<figref idrefs="f0002">figure 2</figref>).

p0008In a second Variate the positive fit both retaining device and retaining region is substantially dimensionally stable and enclosing the holding area are carried out by the holding device by interengagement of the given moving through these two units forms. Since the units are dimensionally stable, no complete enclosure is possible, but the forms must be open to the extent that they can be reciprocally moved. The intertwining move takes place (at least with a travel component) transversely to the puncturing direction and there is a coupling that is substantially free of play in the puncture direction is also (see<figref idrefs="f0004">figure 4</figref>). Finally, it is also a coupling by a movement possible that both components across as having also parallel to the puncturing direction (see<figref idrefs="f0007">figure 7</figref>).

p0009The system for removing blood has a drive unit with a plunger through which a lancet is moved from a resting position into a lancing position. In the prior art a number of drive mechanisms are known, which can be used in the area of ​​blood collection devices. In particular, large-scale drive mechanisms are used that draw their energy from a previously tensioned spring. In the present invention, the drive units are preferably used, which due to the form-locking coupling that enable a guided movement of the plunger and the lancet. With a guided movement is meant that the lancet engraved both a predetermined path into the body than is drawn out also through a predetermined path-time curve from the body. In the conventional, on a combination of a spring and a stop based system of the prior art, the path-time course is .als influenced by a variety of parameters, such as manufacturing tolerances (friction conditions in the system, strength of the spring) and the skin surface. It has been shown that a guided movement of the lancet, as the example, via a guide slot as in<patcit id="pcit0007" dnum="EP565970A"><text>EP 565 970</text></patcit> described advantageous with respect to the puncture pain is. Regarding the drive unit is hereby to the preferred drive mechanisms of<patcit id="pcit0008" dnum="EP565970A"><text>EP 565970</text></patcit> and the <patcit id="pcit0009" dnum="US4924879A"><text>US 4,924,879</text></patcit> Referring.

p0010An important aspect is a removable from the drive unit lancing unit in which at least one lancet is located. The lancing unit comprising a housing in which the lancet is arranged in the rest position. This can be avoided that are caused by the lancet before or after use injury or contamination that occur. The housing may be configured so that therein a single lancet is disposed or the housing may take the form of a magazine with a plurality of lancets. As a rule, the lancets are located within a magazine in mutually separated chambers, to prevent contamination of unused lancets by already used. The housing of the lancing unit is advantageously designed so that it can be attached to the drive unit. For this purpose, the lancing unit may for example have the shape of a cap, which is plugged onto the drive unit. Such embodiments are disclosed in the documents<patcit id="pcit0010" dnum="US5314442A"><text>US 5,314,442</text></patcit>. <patcit id="pcit0011" dnum="US4990154A"><text>US 4,990,154</text></patcit> and <patcit id="pcit0012" dnum="US5074872A"><text>US 5,074,872</text></patcit> described. There are also embodiments are possible in which the lancing unit is firmly connected with the drive unit, or forms an integral part of the drive unit. This may be particularly advantageous in systems with magazine, so that the entire unit is discarded after consumption of the magazine. In the case of a piercing unit in the form of a magazine that may, for example arranged side by side chambers, in which there are lancets and the chambers are sequentially positioned relative to the drive unit so that the lancet can be coupled to the plunger of the drive unit. Also particularly advantageous is a magazine in the form of a drum with parallel to the longitudinal axis of the drum arranged chambers, in which there are lancets. Similar to a revolving drum can be reproducibly attached to the drive unit such a magazine.

p0011Another requirement of the lancing unit is the sterility of the lancet, which must be guaranteed over a long period. A sterility of the lancing unit can, as usual in the art, are achieved by gamma irradiation. To maintain the sterile conditions, the lancing unit in an outer packaging, such as a polyethylene bag to be welded. In another embodiment, the openings of the piercing unit are closed (for the entry of the plunger and the outlet of the needle tip) by sealing films. This may for example be peelable sealant films which removes the user before use. Advantageously, however, thin films can be used, which are pierced in the use of the plunger or the needle tip so that the user is spared additional handling steps. Such films may already be integrally produced in the manufacturing process of the lancing unit, which is an injection molding process as a rule.

p0012In a further advantageous embodiment, the needle tip is protected by an elastomer against contamination, which is taken off prior to the closure or is pierced during the engraving process to release the needle tip. Such protection of the needle from contamination in the<patcit id="pcit0013" dnum="WO0166010A"><text>WO 01/66010 application</text></patcit> described to which reference is hereby made.

p0013Within the lancing unit are one or several lancet with a needle. In addition to any devices on the lancet, which allow a form-fit coupling to a plunger of this invention lancets can be used in the frame, as they are well known in the art. Normally, such a lancet has a base body made of plastic, in which a metal needle is placed. However, also lancets without a separate greenbody possible (for example, metal needle with a thickening at the rear end as a holding area).

p0014In the present invention, it is important that the plunger of the drive unit and the lancet for execution of the pricking operation are coupled to each other by positive engagement. Herein, the invention differs substantially from the prior art, where a mechanical coupling between the lancet and drive via an interference fit (<patcit id="pcit0014" dnum="US5314442A"><text>US 5,314,442</text></patcit>. <patcit id="pcit0015" dnum="US4990154A"><text>US 4,990,154</text></patcit>. <patcit id="pcit0016" dnum="US5074872A"><text>US 5,074,872</text></patcit>), A catch (<patcit id="pcit0017" dnum="WO0002482A"><text>WO 00/02482</text></patcit>), Jamming (<patcit id="pcit0018" dnum="US3030959A"><text>US 3,030,959</text></patcit>) Or via a simple contact pressure (<patcit id="pcit0019" dnum="DE19855465"><text>DE 198 55465</text></patcit>) Takes place. A form-locking is characterized in that a mechanically reliable coupling between the actuator and the lancet is carried out without the need for a substantial pressure force is effected to the lancet toward the puncturing movement. In the devices of the prior art, which work with a press fit, must be in the cap, which includes the lancet, a spring element (eg. B.<patcit id="pcit0020" dnum="DE19855465"><text>DE 198 55 465</text></patcit>) Or a retaining element (eg. B. <patcit id="pcit0021" dnum="WO0002482A"><text>WO 00/02482</text></patcit>be) provided, which is designed so that the lancet during the coupling of the lancing unit does not leak to the drive unit from the cap. However, spring elements in the lancing unit lead to increased manufacturing costs, which is particularly serious since it is consumable during the lancing unit. To overcome a retaining member on the other hand, an additional force is required on the part of the drive unit and overcoming also leads to vibrations of the needle, the negative effect on the bite pain. Moreover, it is problematic in systems that operate with a press fit, a guided movement, which involves retraction of the lancet, as a result, the interference fit can be solved. The in<patcit id="pcit0022" dnum="WO0002482A"><text>WO 00/02482</text></patcit> Catches at described solves this problem though, but it is difficult to obtain. In particular, it is difficult, such catches at establishing in a continuous manufacturing process, since even slight variations pull the material or process conditions inoperability of the device to be. Another disadvantage of the<patcit id="pcit0023" dnum="WO0002482A"><text>WO 00/02482</text></patcit> device described is that the latching of paths takes place in a region which serves for insertion into the body. The force variations and vibrations occurring in the catches at have a detrimental effect on the puncture pain. A disadvantage of the device further in that the needle remains after the puncture in the body and is not actively retracted. A needle retraction occurs only when the cap is removed from the drive mechanism. In a positive locking of the drive plunger and lancet according to the present invention, however, a connection between the plunger and lancet can be achieved without requiring a special power would be expended in the direction of the stitch and about h inaus can the positive connection advantageously be used, the needle actively withdraw after the puncture. This ability to actively manage the travel-time curve of the needle through the drive unit, it is possible to customize the lancing process very painless.

p0015In <figref idrefs="f0008">figure 8</figref> are schematic force (F) pathway (s) coupling procedure of sessions for processes of the drive to the lancet for interference fit (a), latching of (b) and positive locking (c). It can be seen that when the press fit, the force increases rapidly until the lancet from the position in which it is held by a holding member or a spring, triggers. In a latching of the force increases the locking and decreases after successful conclusion again. With a form-fitting only very small forces for moving together of the holding elements are necessary.

p0016Another characteristic of form fit is determined by comparison with the document <patcit id="pcit0024" dnum="US3030959A"><text>US 3,030,959</text></patcit> significantly. In an apparatus according to this US patent are needles which are arranged in a tube one after the other supported by a clamping device which is similar to a mechanical pencil. In addition to the contamination problems with used needles, which makes this apparatus unresolved, it can be seen that the positioning of the needles in the axial direction is not defined (ie, in the puncturing direction). Just as in a mechanical pencil, the length of the protruding pencil tip by the user can be freely selected, the axial positioning of the needle on the setting here depends on the user. With a form-fitting principle, however lancet and drive unit have concerted holding areas and holding devices. Due to the geometric configuration of the holding area and retaining device can be achieved in that the axial positioning of the lancet is well defined and thus the piercing depth can be accurately controlled. , by using an interlocking connection thus both a peak force in the axial direction can be avoided in the coupling of the lancet and plunger drive as well as a precise axial positioning can be achieved. With a form-fitting to a shape (holding device) includes a different type (holding area). Under a self-closing is meant in this sense, both a movement of parts of the apparatus transversely to the puncturing direction and alternatively, a positive engagement of two unchanged in shape moldings. In a preferred embodiment the holding device is opened and closes around the holding area when the latter is introduced into the holding device. In particular, this closure can be effected by a longitudinal movement in which the longitudinal movement is converted into a movement of holding members of the holding device with components transverse to the longitudinal direction of movement. A practically advantageous way to achieve this transformation a length motion in a transverse movement is to the fixture with the longitudinal movement in a tapered channel (eg in a sleeve) introduce or move in this (see<figref idrefs="f0001">figure 1</figref>). rejuvenating Among these are not only continuously tapering channels are understood but in general channels whose clear width is reduced in the longitudinal direction. A channel need not be closed over a peripheral surface of the body in this context. When the holding device, for example as described in<figref idrefs="f0001">figure 1</figref> has two opposing hooks, satisfy two walls whose inner distance is reduced to one another. There is on the other hand also the possibility to close the holding device by releasing a tensioned condition (see <figref idrefs="f0002">figure 2</figref>), Resulting in a widening channel is possible, for example, by movement of the holder.

p0017The present invention is further illustrated by means of figures:<ul><li><figref idrefs="f0001">figure 1</figref>: Cross-sectional view of a lancing unit having a holding device on the lancet</li><li><figref idrefs="f0002">figure 2</figref>: Cross-sectional view through a system clipping with a retaining device to the drive unit</li><li><figref idrefs="f0003">figure 3</figref>: Cross-sectional view through a complete system and steps of use</li><li><figref idrefs="f0004">figure 4</figref>: System segment with dimensionally stable holding device to the drive unit</li><li><figref idrefs="f0005">figure 5</figref>: Magazine of lancing units</li><li><figref idrefs="f0006">figure 6</figref>: System of drive unit and lancing unit</li><li><figref idrefs="f0007">figure 7</figref>: System with a dimensionally stable holding device</li><li><figref idrefs="f0008">figure 8</figref>: Force-path diagram for different coupling types</li><li><figref idrefs="f0009">figure 9</figref>: Lancing unit with sterile protection</li><li><figref idrefs="f0010">figure 10</figref>: Drum-shaped magazine</li></ul>

p0018<figref idrefs="f0001">figure 1</figref> shows a blood collection system according to a first embodiment of the invention in the actuating phases I, II and III. In the<figref idrefs="f0001">figure 1</figref> are shown only partial aspects of the system. In the illustration, the drive unit for the plunger (10) and the housing of the drive unit is missing, at which the lancing unit (20) is attached. The drive unit for the plunger (10) is in the<patcit id="pcit0025" dnum="EP0565970A"><text>EP 0565970</text></patcit> Drive device described is particularly suitable.

p0019The in <figref idrefs="f0001">figure 1</figref> Phases illustrated show the realization of the positive coupling between the drive ram (10) and the lancet (30), and the actual lancing process. For each of the three phases in each case 2 cross-sectional views along the longitudinal axis of the system are shown in mutually perpendicular planes. From the left of the phase I it can be seen that the lancet (30) is arranged within a sleeve (40). The lancet (30) shown has a base body which is made of plastic and a needle is injected (31) from steel. At the side facing away from the needle tip the lancet has a holding device with holding elements in the form of two hooks (32a, 32b). During retraction of the plunger (10) in the lancet enters a thickened region at the front end of the plunger which serves as a retaining area (11) between the hooks (32a, 32b) and finally collides with the rear needle end (phase II). It is also possible to let the tappet instead impinge on the rear needle end to the base body of the lancet. Direct contact with the needle is advantageous, however, because the needle length can be production-controlled very precisely and thus accurate control of the insertion depth is possible. Upon further advance of the plunger, he pushes the lancet inside the sleeve (40) in the direction of the outlet opening (41), so that, finally, the needle tip protrudes beyond the outlet orifice and pierces an underlying tissue. From the transition from phase 11 to phase III it can be seen that closing the holding devices (32a, 32b) on the lancet to the holding area (11) of the plunger, when the lancet is moved within the sleeve (40). The holding device of the lancet surrounds the holding element of the ram so that a positive connection is formed with not only a forward movement of the lancet to execute a stitch but also an active and controlled by the drive unit retracting the lancet is substantially free of play possible. This is on the one hand ensured that the end of the holding area on the needle end is seated and by the hooks (32a, 32b) which engage behind the rear end of the holding area. The length of the holding area and the longitudinal extension of the chamber in the closed holding device are coordinated so that a play-free drive of the lancet is placed in the puncture direction. The arrangement of the lancet or of the holding device in a tapered sleeve converting a longitudinal movement of the lancet in the puncture direction is achieved in a transverse movement of the elements of the holding device, which allows a positive connection with the holding area of ​​the drive. As can be seen from the figures, the sleeve (40) has a central region (40b) (40a) is tapered towards the upper region. Due to this taper, the hooks (32a, 32b) are pressed together the lancet during the displacement of the lancet in the sleeve in the direction of the longitudinal axis, so that an enclosing of the holding area (11). Especially advantageous has proven the lancing unit (20) in such a way that the lancet is held within the sleeve, if no action of the ram is present. This can ensure that the needle in the non-activated state within the sleeve (40) and thus no injury or contamination by an outstanding needlepoint caused. A sliding through of the lancet through the sleeve in the direction of the outlet opening (41) is effectively prevented in that the hooks (32a, 32b) have a shoulder which rests on an edge of the central region (40b). The inclination of this edge and the flexibility of the hook can be so each adapted to an insertion in the taper on the one hand can be carried out with little force and, secondly, an unintentional sliding through is effectively avoided. To slipping out of the lancet out of the sleeve, in which the stitch direction opposite to avoid, in the illustrated embodiment is a widened portion (40c) at the lower end of the sleeve as well as an order corresponding widened part (30a) provided at the lower end of the lancet body.

p0020As shown in Figure III, the needle tip is when striking the holding area (11) on the needle end is still within the sleeve (40). This is advantageous because the vibration generated by the impact does not affect the casting process in the tissue, thereby piercing pain is avoided by such vibration.

p0021According to the invention, it is preferred if the system is designed so that after passing through the Phase I, II and III, a return movement of the plunger (10) is in the reverse direction so that the push rod is decoupled from the lancet and the lancet back completely within the sleeve is. For coupling of the ram to the lancet there are two main variants. In the first variant housing, drive unit and lancing unit are adapted to each other that the plunger is in the initial state completely outside the lancing unit (20) (as shown for phase I). A disadvantage of this embodiment is that a relatively long way to be traveled by the plunger for performing a stitch. An advantage, however, is that the plunger completely outside the sleeve so that a transverse movement is possible. Accordingly, the first variant can advantageously be used for systems with a lancet magazine can be moved in the various successive pods beneath the pusher. In a second variant according to a positioning phase II or even better is achieved towards Phase III by coupling the lancing unit to the drive unit already. In such an embodiment, the path of the plunger must be done, can be kept very small, which is constructionally favorable.

p0022<figref idrefs="f0002">figure 2</figref> shows a second embodiment of the invention, wherein the lancet (130) has a holding area (131) and the drive unit, a holding device (132a, 132b) has. In the<figref idrefs="f0002">figure 2</figref> in turn, is the portion of the system shown, which serves to hold the lancet, but not the drive unit. Also in connection with this embodiment it is advantageous to use a drive unit that moves out the plunger (110). The plunger carries at its front end a holding device with holding elements in the form of two hooks (132a, 132b) which are on a flexible bridge (133) (or joint) connected to each other. The arrangement forms a spring element. In phase I, these hooks are spread apart because their rear ends are held together by a sleeve (140). Upon insertion of the lancet (130) at the same time the sleeve is moved against a spring (141), so that the rear ends of the hooks are released and the front ends of the hook form-fitting manner to the retaining portion (131) close the lancet. The holding portion of the lancet has a recess (recesses) into which the hook of the retaining device. The longitudinal extent (in the puncturing direction) of the engaging ends of the holding device and the longitudinal extension of the recesses are substantially the same, so that a guided, essentially free of play piercing movement can be performed with this arrangement. Also in this embodiment there is a conversion of a longitudinal movement of the holding device into a transverse movement of the retaining elements.

p0023<figref idrefs="f0003">figure 3</figref> shows an inventive system, based on the positive coupling principle according <figref idrefs="f0002">figure 2</figref>, The drive unit 100 based on the device Softclix®, which in the<patcit id="pcit0026" dnum="EP0565970B"><text>EP B 0565970</text></patcit> is described. From this document it is apparent in particular, as mediated by the drive spring 170 rotational movement of the sleeve 171 into a translational movement of the push rod 110 is implemented. The tensioning of the drive spring by depressing the push button 172 and therefor suitable mechanical translation are described in the European patent application with the application number EP 0 O10 2503.0. The drive unit has, at its front end a holding device with two holding elements, in the specific case hooks (132a, 132b) on. As to<figref idrefs="f0002">figure 2</figref> executed, these hooks in a central area via a flexible bridge (133) or a hinge, connected to each other. On the hook relative to the bridge (133) facing away from the holding device is supported on a sleeve (140) so that the hooks are open. The sleeve (140) is held on a present in the drive device spring (141) in position. Out<figref idrefs="f0003">3 I</figref> is also a lancing unit to recognize, when a lancet (130) is arranged in a cap (121). The lancet has at its rear end a retaining portion (131) of the holding device (132a, 132b) is gripped. The outer body of the lancet comprises a front, narrow region and a flange (122) between said narrow area and the holding area (131). The tip of the lancet is protected by a twist-off plastic body (123) from contamination and mechanical damage. The cap (121) has in its interior a passage for the narrower region of the lancet and an enlarged cross-sectional area which is suitable for receiving the flange (122). Within this widened channel of the cap, a bead (124) is arranged, which prevents unintended slipping of the flange in the extended channel. The cap further has a sleeve (125), which serves to push back the sleeve (140) of the drive unit while placing the lancing unit to the drive unit. This process can be carried synopsis of<figref idrefs="f0003">Figures 3I and 3II</figref> recognize. By pushing away the sleeve (140) by means of the sleeve (125), the holding device is released so that it includes the holding area of ​​the lancet, such as from<figref idrefs="f0003">figure 3II</figref> can be seen. By pressing the button (172) and trimming the guard member (123) of the lancet is prepared the system now for use. With the in<figref idrefs="f0003">figure 3II</figref> Apparatus shown is now carried out a lancing process, which placed the front end of the cap (120) to a tissue part and by actuating a trigger mechanism, the drive unit is activated. After the lancing process the cap of the drive unit is withdrawn along the longitudinal axis, wherein the flange (122) is pulled back behind the bead (124), so that the contaminated needle tip can not leak out of the cap. The lancing unit in the state of<figref idrefs="f0003">3 III</figref> can be discarded, or be used by coupling to the drive unit for further removal operations.

p0024<figref idrefs="f0004">figure 4</figref> shows a third embodiment of the invention in which the positive engagement between the lancet and driven by a positive connection of geometrically adapted to each other and holding areas holding devices is achieved. In the<figref idrefs="f0004">4A</figref> is a piercing unit (220) illustrated that comprises a sleeve (240) in which there is a metal needle (231). The sleeve (240) has a thin transverse wall (250) which supports the metal pin relative to the sleeve. This transverse wall is preferably the same shape during encapsulation of the needles with plastic. Due to the relatively small thickness of this wall, the mechanical connection of the sleeve and needle during the lancing process can be solved, so that the needle slides past the wall (250). At the outlet of the sleeve this with a thin film (260) is closed, which is pierced upon lancing process. At its upper end the needle (231) carries a molded-holding area (232). For mechanical stabilization, the needle has a taper at which the retaining area (232) is injected so that an axial sliding through is avoided. A holder of the needle into the sleeve can also be achieved by roughening the needle on its outer surface, a thickening or curvature of the needle in the region of the sleeve. The actuator stem (210) of this embodiment has, at its lower end on a holding device (211), form-locking comprises the retaining portion (232), as shown. The holding device (211) is open at the side, so that the plunger displaced parallel to the needle to the holder (211) to the height of the holding area (232) are driven and by displacement transverse to the needle axis and to the puncturing direction with the holding portion of the needle engaged can be brought. After this positive engagement thus obtained, the needle can be driven both in the puncture direction of the plunger (210) as well as active retired. In the example shown, the holding area of ​​the lancet in a recess (depression), in which when coupling a projection of the holder engages, so that the two bodies are largely connected with each other without clearance with respect to the puncture direction.

p0025In the <figref idrefs="f0004">4B</figref> is a magazine shown, which consists of puncturing units (220) in accordance with <figref idrefs="f0004">4A</figref> is constructed. Based on the coordinate system shown, the drive ram (210) (perpendicular to the plane of the drawing) are brought into engagement with the holding portion of the lancet or of the form-locking are also canceled again by movement in the Y direction. With uplifted positive engagement of the drive ram in X-direction (left / right) can be moved at the level of another lancet and brought by motion in the Y direction again engaged therewith, so that the lancet magazine can be successively processed. In existing form-fit an active movement of the needles in both positive and negative Z-direction (up / down) is possible.

p0026Alternatively, according to the coupling <figref idrefs="f0004">4B</figref>That both requires a movement of the plunger drive in x as well as γ-direction, can also be a coupling moving through a movement only in x direction. The drive ram has for this purpose, for example, two opposing hooks between which a passage for the holding area of ​​the lancet is provided in the x direction. By moving in the x direction of the plunger can now be moved from lancet to lancet to perform a sting operation in the z direction. the drive plunger is in the x direction at the level of a lancet, the holding device of the plunger comprises the holding area of ​​the lancet positively and this can be moved out by the plunger in the z direction, the tappet therefore results in a pricking movement and also pulls the lancet active again back.

p0027In <figref idrefs="f0005">figure 5</figref> is a system working automatically with lancing units according <figref idrefs="f0001">figure 1</figref> shown. As shown in the plan view (<figref idrefs="f0005">5B</figref>can be seen), the lancing units (20, 20 'etc) mounted side by side on a conveyor belt. The conveyor belt (301) passes around two spaced apart rollers (302, 303). One of the rollers is driven by a motor so that the lancing units successively by a coupling position (305) are moved. , Is in this position as in<figref idrefs="f0004">4a</figref> shown, an interlocking coupling of a drive plunger (10) to a position in the puncturing (305) located lancing unit (20) possible.

p0028<figref idrefs="f0006">figure 6</figref> shows a drive unit, to which a lancing unit analogous to the embodiment in <figref idrefs="f0001">figure 1</figref> is coupled. The illustrated drive system corresponding to the European Patent Application Serial<patcit id="pcit0027" dnum="EP00102503A"><text>00102503.0</text></patcit>, In this drive system a sleeve (414) is axially rotated by the pressing of a push button (420) against the tension of a spring (418) so that a second spring (415) is tensioned. The sleeve (414) is locked in an end position, so that the second spring (415) remains tense. If the user cancels the locking, the spring (415) and the sleeve (414) laid is rotated in the opposite direction as during the clamping operation. In the sleeve (414) is a groove which serves as a slotted guide for the propulsion cylinder (408) having a pin or the like carrying on its outer surface which engages in the groove. The rotation of the sleeve (414) is converted into a translation of the propellant cylinder. The propellant cylinders transfers its driving to the driving ram (480) having a holding area at its front end.

p0029The drive unit further includes a holding area (450) on which a lancing unit can be fitted or turned up. The lancing device includes a cap (470) having a surface for pressing against the skin surface. In the cap, a sleeve (471) is arranged in which a lancet (472) with holding devices on its, the needle tip side opposite has. The holding device of the lancet corresponds to the holding devices (32a, 32b) of the<figref idrefs="f0001">figure 1</figref>, Out<figref idrefs="f0005">figure 5</figref> can also be seen that a positive connection of the lancet and plunger drive already by attaching the cap (470) is obtained at the drive device.

p0030<figref idrefs="f0007">figure 7</figref> shows a system for withdrawing body liquids, which in a number of similarities to the <figref idrefs="f0003">figure 3</figref> System shown includes. In particular, in the<figref idrefs="f0003">figure 3</figref> and <figref idrefs="f0006">figure 6</figref> reference was made describing the drive and clamping mechanism. The system of<figref idrefs="f0007">figure 7</figref> includes a lancing unit (120 ') with a cap (121') and a lancet (130 '). In the cap (121 ') is an axial passage through which the lancet body can pass during the lancing process. Preferably both passage and lancet body are coordinated so that an axial guidance of the lancet is given during the lancing process with only slight play in the transverse direction. At its rear end, the cap has a thread (126) on a corresponding thread (127) can be screwed on the drive unit (100 '). At the needle tip the opposite end having the lancet park one or more (in the illustrated case 2) pins (131 ') formed on the drive unit in the form of an end to the holding device (132 during placement or unscrewing the cap' reach). The holding device has for this purpose a recess or groove having an axial portion (134a) and a part arranged transversely thereto (134b). When the cap is placed on the drive unit, the pins (131 ') enter into the axial portion of the groove (134) and pass through the latter. Up to the height of the transversely arranged portion of the groove By loosening the cap (120 ') to the driving unit (100') of the pin (131 ') is moved from the end of the axial part in the cross part of the groove to the opposite end. As from<figref idrefs="f0007">figure 7II</figref> It can be seen, the lancet is held axially by means of the pin by the retaining device (132 '), so that a guided puncturing movement can be performed with the lancet. Due to the positioning of the pins in the cross section of the grooves can be made with the lancet both a movement for the exit of the needle tip and a retraction. As from<figref idrefs="f0007">figure 7</figref> be seen, the positive connection between the lancet and holder can be obtained without any jamming or locking is carried out. This in<figref idrefs="f0007">figure 7</figref> illustrated coupling principle of the lancet and plunger drive is of course also reciprocally, that is possible with a corresponding retaining means on the lancet and a retaining portion on the plunger or actuator.

p0031<figref idrefs="f0009">figure 9</figref> shows a further development of the system of <figref idrefs="f0001">figure 1</figref>, The drive ram (10 ') has a holding area (11') which has a peripheral inclined surface on its upper side, which, as in<figref idrefs="f0009">figure 9B</figref> to recognize, during the lancing process in fit with inclined surfaces of the hook (32a ', 32b') comes. The end of the drive plunger is seated on the needle end during the compression of the contained flexible hooks (32a ', 32b') causes bevels are pressed against the hook inner side bevels on the top side of the holding area, so that the holding portion is pressed onto the needle end will and without play in the puncture direction of connection holding section and lancet arises. This fit very precise positive retention between lancet and driving plunger can be achieved, the (manufacturing) compensates tolerances so that a game is avoided both in engraving and in the retracting movement. The holding device in the form of hooks (32a ', 32b') is further so designed that the free ends of the hooks in cutouts in the sleeve (40 ') engage. This avoids that the lancet (30 ') from the sleeve (40' may slip unintentionally). As from the transition from<figref idrefs="f0009">9A</figref> to <figref idrefs="f0009">figure 9B</figref> can be seen, the free ends of the hooks are first dissolved at the start of the piercing operation from the recesses and the hooks are compressed when inserted into the tapered sleeve, so as to enclose the holding area of ​​the drive ram.

p0032In the <figref idrefs="f0009">figure 9</figref> will also be appreciated that the needle tip (31 ') is arranged in a material (35). This material (35) is preferably an elastomer, which surrounds the needle tip tightly, so that contamination of the needle tip is effectively changed. Suitable elastomers are: styrene oligoblock copolymers, thermoplastic polyolefins, thermoplastic polyurethanes, thermoplastic copolyesters and thermoplastic copolyamides. For further details on this procedure, to avoid contamination of the lancet tip, is hereby to the international<patcit id="pcit0028" dnum="WO0166010A"><text>WO 01/66010 application</text></patcit> Referring. In the initial position shown in Figure A in front of the stitch, the needle tip is in the elastomer and is pierced when performing a stitch of the needle, as can be seen from Figure B. For this purpose, the sleeve (40 ') at its bottom to a plate (36) with a central opening. The plate prevents leakage of the elastomer through the opening so that it is pierced, while the needle exits through the central opening. Upon retraction of the lancet remains the elastomer on the needle, now the needle tip is exposed (see Figure C).

p0033<figref idrefs="f0010">figure 10</figref> shows in cross section (<figref idrefs="f0010">figure A</figref>) And in perspective view (<figref idrefs="f0010">figure B</figref>) A cylindrical magazine based on lancet according <figref idrefs="f0001">figure 1</figref> or. <figref idrefs="f0009">figure 9</figref>, With such a magazine, it is possible to attach easily new lancet to the drive. For example, use of the drive ram stationary relative to be arranged a lancing device and in<figref idrefs="f0010">figure 10</figref> represented, drum-shaped magazine is similarly turned a revolving drum, so that unused lancets reach the position for coupling the drive ram.