EP1998672A2 - Test system comprising a test unit for analysing body fluids - Google Patents

Abstract

The invention relates to a test unit for analyzing body fluids, comprising a collecting element (14) that is provided with a microfluidic collection zone (36) for the body fluid, and a test element (16) which can be fluidically connected to the collection zone (36) by deflecting a transfer part (34) of the collecting element (14) in order to transfer body fluid. According to the invention, the transfer part (34) is preloaded against a retaining mechanism (20), deflection of the transfer part (34) towards the test element (16) being triggered by detaching the retaining mechanism (20).

Description

Test unit and test system for examining body fluids

description

The invention relates to a test unit and a test system for examining body fluids such as blood according to the preamble of claims 1 and 17, respectively.

From WO 2005/084530 a collecting device for Körperflüssigkei- th is known, in which a movable part of a flow path for the body fluid is actively brought by a contacting agent with a receiving means for the liquid in connection, for example, by a mechanical or magnetic actuator movement is driven. Thus, a small amount of liquid can be subjected to processing in a test process at a defined time. With regard to the relevant prerequisites and advantages, reference is expressly made to the above-mentioned printed description and its content is included here. However, the active contacting requires a device-side drive unit, which increases the manufacturing outlay and complicates the process flow. In particular, care must also be taken to ensure the required accuracy in the interaction between the device drive and the moving element as part of a disposable.

Proceeding from this, the object of the invention is to further develop the units or systems known from the prior art so that a controlled measurement sequence with high reliability is made possible with simpler means.

To solve this problem, the combination of features specified in the independent claims is proposed. Advantageous embodiments and modifications of the invention will become apparent from the dependent claims. The invention is based on the idea to be able to do without an external drive by an inherent transfer movement. Accordingly, the invention proposes that the transfer part is biased against a hold-down, wherein the deflection of the transfer part to the test element can be triggered by releasing the hold-down. By the bias, an automatic movement between an initial state and a contact state take place, wherein the initial state is obtained by the hold-down as a retaining means until the triggering occurs. For this, only low accuracy requirements arise, since the movement of the transfer part as such requires no external control or guidance. Incidentally, however, the already mentioned advantages of a time-defined triggering of the test process are fully achieved. Above all, this has a positive effect on disposable articles in which microfluidic processes, preferably under capillary action, transfer the smallest sample quantities (for example microliters and less) from the place of extraction to the site of the test execution.

Advantageously, the collection area extends at least partially over the transfer section, wherein the collection area and the test element are physically separated at a distance from one another and after the deflection in contact with each other before the deflection. In this way, the liquid intake can take place even under difficult conditions, while only after successful completion of the collection process a targeted sample transfer takes place.

A structurally advantageous embodiment provides that the transfer part is preferably mounted with a pre-bend as a bending arm on the collecting element.

For an inherent transport movement by deformation, it is advantageous if the transfer part can be deflected by the action of internal stresses and / or surface tensions under bending deformation. This can be realized by the transfer part being characterized by a different upper Surface treatment on different sides has a deflection causing bending stress. Another possibility is that the transfer part can be deflected by different material layers in the manner of a bimetallic strip. In terms of manufacturing technology, it is particularly simple if the transfer part is formed by an etching process from a flat substrate, wherein internal bending stresses resulting from different etching depths on different sides of the transfer part exist in the transfer part. In this way, no additional bending process is required since the bending prestress is already obtained by a process step of a molding process suitable for mass production.

It is also conceivable that the transfer part can be deflected by plastic deformation. Such deformation can be carried out in the manufacturing process as a pre-bend or only in the use of equipment.

A further advantageous embodiment provides that the collecting element has a piercing member for piercing a body part, for example, in the finger, wherein the collecting area is acted upon by the puncture with body fluid.

In order to determine the initial state of the transfer part in a simple manner, the hold-down can be formed by a separable material bridge between the collecting element and the transfer part, wherein the deflection of the transfer part can be triggered by severing the material bridge. This can be accomplished particularly simply by the fact that the collecting element and the hold-down are integrally formed from a flat material, in particular a stainless steel sheet, wherein the hold-down is formed by at least one separable web.

Alternatively, it is also possible without any particular manufacturing difficulties that the hold-down device is formed by an adhesive strip or a laminate applied to the collecting element and thereby covering a portion of the transfer part. To prevent premature fluid transfer, it is advantageous if the test element is preferably arranged in the initial state by a spacer on the collecting element at a predetermined distance from the transfer part.

Advantageously, the collecting element and the transfer part form a unit intended as disposable disposable product.

In order to enable a targeted transfer of even the smallest sample amounts, it is advantageous if the transfer part comes into contact state while maintaining a predetermined contact angle with the test element in engagement.

The test element may have a reagent field which can be acted upon by the body fluid via an opening of the collecting region, in particular a longitudinal opening of a capillary channel.

The invention also encompasses a test system for examining bodily fluids, such as blood, in which the transfer part is biased against a hold-down on the collection element, wherein the deflection can be triggered by releasing the hold-down device by means of a device-side release.

It is possible that the trigger is formed by a non-contact separation unit, in particular a laser. Another variant provides that the trigger has a mechanically effective cutting means. It is also conceivable that the trigger is formed by a thermal actuator for triggering a bending deformation under the action of heat.

Advantageously, the test element in the system is handled or positioned independently of the collecting element, in particular in order to transfer a quantity of liquid to a separate measuring point. In the following the invention will be explained in more detail with reference to the embodiments schematically illustrated in the drawing. Show it:

1 shows a test system with collection and test element for recording and examining blood in a block diagram;

2 shows the collecting element with a transfer part for the blood sample in a pre-bent state in a perspective view.

FIG. 3 shows the collecting element according to FIG. 2 in a simplified side view and top view; FIG.

FIG. 4 shows the collection element in a representation corresponding to FIG. 3, additionally with hold-down device and test element in the starting state; FIG.

Fig. 5, the collecting element corresponding to Fig. 4 in triggers

Status; and

6 and 7, a further embodiment of a collecting element with a separating web as a hold-down in Fig. 4 and 5 corresponding representations.

The test system 10 shown in FIG. 1 is preferably designed as a portable blood glucose meter and allows the use of disposable test units 12 for the self-determination of blood sugar by the patient. For this purpose, each test unit 12 comprises a collecting element 14 for receiving a microscopic amount of blood and a test element 16, which is acted upon by deflection of a transfer member 18 of the collecting element 14 with blood, the transfer member 18 held by a hold-down 20 in the initial state of the test element 16 is. As further system units, a trigger 22 for the hold-down 20, a lancing drive 24 for the collecting element 14 and a measuring unit 26 for a preferably optical scanning of the test element 16 are provided. A processor unit 27 enables the device-related process control and evaluation of the measurement results.

As shown in Fig. 2, the collecting element 14 from a flat substrate 28, in particular stainless steel sheet is integrally formed by etching. In this case, a distally protruding, needle-shaped shaft shaft 30 is integrally formed on the substrate part 28, while in the region of a central substrate recess 32 a pre-bent transfer part 34 is freed. Between the shaft 30 and the transfer section 34 there is a continuous groove-shaped half-open capillary channel 36 for transporting the blood sample obtained by a puncture into a body part.

As can also be seen in FIG. 3, the transfer part 34, as a curved bending arm, is bent out of the plane 38 of the substrate 28, to the side on which the channel 36 is laterally open. The pre-bend can be effected, for example, in that the bending arm 34 undergoes a bending deformation under the action of internal stresses and / or surface tensions. Especially during the etching process, as a result of different etch depths or asymetric etching on the opposite substrate sides of the transfer part 34, resulting internal bending stresses can remain. Another possibility is a one-sided physical or chemical surface modification or treatment. It is also conceivable that by laminating a further film layer on the transfer section 34, a two-layer strip is formed, which is deflected due to different coefficients of linear expansion in the manner of a bimetallic strip under the action of heat.

According to FIG. 4, the transfer part 34 is held in the substrate plane 38 by a detachable hold-down 20. The hold-down 20 may for example be an adhesive strip which is glued to the substrate 28 and the Recess 32 and the proximal portion of the transfer member 34 spans so that the curvature of the transfer member 34 is held down. In this way, in the initial state, a clear free space 40 is kept free toward the test element 16, as a result of which there is initially no fluidic connection between the collecting duct 36 and the facing side of the test element 16. The air gap 40 thus prevents blood collected in the collection channel 36 from being transferred directly to the test element 16.

The test element 16 can be formed by a reagent strip which is coated with dry chemicals which respond to an analyte (glucose) in a body fluid (blood, possibly also tissue fluid), for example by color change, so that optical detection is possible. The reagent strip 16 is supported by spacers 42 in the region of the substrate 28 to provide the clearance 40 to the down-held transfer member 34.

As illustrated in FIG. 5, the hold-down device 20 can be released or separated by means of the trigger 22, so that the transfer part 34 is laterally deflected at a defined triggering time due to the impressed pre-deflection and the channel 36 is in fluidic contact with the test element 16 is coming. This can be accomplished by the trigger 22 driving a laser 46 (FIG. 1) as a separation unit in order to cut through the hold-down 20 on both sides of the transfer part 34. In this case, the transfer member 34 curves automatically upwards, so that a contact state with the test element 16 is achieved and transmitted via the longitudinal channel opening blood fluid as a sample spot 44. Due to the bending of the transfer part 34, the intervention can be achieved while maintaining a predetermined contact angle, whereby a locally targeted blood transfer with a high positioning accuracy is possible.

Instead of a non-contact separation unit 46, a mechanical cutting means may also be provided in order to cut through the hold-down 20. NEN. It is also possible for a hold-down member laminated over the transfer member 34 to perform a dual function by providing deflection on the one hand and deflection on the other hand by thermal activation or heat action in the manner of a bimetal.

In the embodiment shown in Figs. 6 and 7, the same or similar parts are provided with the same reference numerals as described above. The hold-down device is here formed by a separable material bridge in the form of a web 20 between the substrate 28 and the proximal end of the transfer part 34. This web 20 can be obtained in the production by not complete Durchätzen the substrate 28, so that no additional components or production steps are required. The release is then carried out after severing this remaining connection 20 with bending of the transfer part 34 in the embossed bending mold (Fig. 7).

When carrying out a test, a test unit 12 is expediently activated from a device magazine in order to gain body fluid by means of the lancing drive 24 in a reciprocating lancing movement via a skin puncture. The liquid transport in the channel 36 then takes place by capillary action, until the collection area in the transfer section 34 is sufficiently filled. From there, the sample 44 can be transmitted to the test element 16 by triggering on the device, whereby constant measurement conditions are created in each test by the defined trigger time. After evaluation by the processor 27, the measurement result is displayed to the user, and the used test unit 12 is disposed of as a disposable product.

Claims

claims A test unit for examining body fluids, such as blood, comprising a collecting element (14) having a microfluidic collection area (36), preferably designed as a semi-open channel, for the Having body fluid, and a test element (16), which is brought into fluidic connection by the deflection of a transfer part (34) of the collecting element (14) with the collecting region (36) for the transfer of body fluid, characterized in that the transfer part (34) against a Hold-down (20) is biased, wherein by releasing the hold-down (20), the deflection of the transfer part (34) to the test element (16) is triggered out. 2. Test unit according to claim 1, characterized in that the collecting area (36) extends at least partially over the transfer part (34), wherein the collecting area (36) and the test element (16) are physically separated at a distance from each other and after the deflection Deflection in contact with each other. 3. Test unit according to claim 1 or 2, characterized in that the transfer part (34) is mounted with a pre-bend, preferably as a bending arm on the collecting element (14). 4. Test unit according to one of claims 1 to 3, characterized in that the transfer part (34) is deflectable by the action of internal stresses and / or surface tensions under bending deformation. 5. Test unit according to one of claims 1 to 4, characterized in that the transfer part (34) by a different surface treatment on different sides has a deflection causing bending stress. 6. Test unit according to one of claims 1 to 4, characterized in that the transfer part (34) is deflectable by different layers of material in the manner of a bimetallic strip. 7. Test unit according to one of claims 1 to 4, characterized in that the transfer part (34) by an etching process from a flat substrate (28) is formed, wherein by different etch depths on different sides of the transfer member (34) resulting inner bending stresses in the Transfer section (34) exist. 8. Test unit according to one of claims 1 to 7, characterized in that the transfer part (34) is deflectable by plastic deformation. 9. Test unit according to one of claims 1 to 8, characterized in that the collecting element (14) has a piercing member (30) for piercing into a body part, wherein the collecting area (36) can be acted upon by the puncture with body fluid. 10. Test unit according to one of claims 1 to 9, characterized in that the hold-down is formed by a separable material bridge (20) between the collecting element (14) and the transfer part (34), and that the deflection of the transfer part (34) under cutting the material bridge (20) can be triggered. 11. Test _unit, said hold-down (20) a separable according to any one of claims 1 to 10, characterized in, are that the collecting member (14) and the blank holder (20) from a flat material, in particular a stainless steel sheet einstü- one piece formed by at least Footbridge is formed. 12. Test unit according to one of claims 1 to 9, characterized in that the hold-down device by a on the collecting element (14) and thereby applied a portion of the transfer part (34) cross-adhesive strip (20) or a laminate is formed. 13. Test unit according to one of claims 1 to 12, characterized in that the test element (16) in the initial state is preferably arranged by a spacer (42) on the collecting element (14) at a predetermined distance from the transfer part (34). 14. Test unit according to one of claims 1 to 13, characterized in that the collecting element (14) and the transfer part (34) form a certain disposable disposable product assembly. 15. Test unit according to one of claims 1 to 14, characterized in that the transfer part (34) comes into contact state while maintaining a predetermined contact angle with the test element (16) into engagement. 16. Test unit according to one of claims 1 to 15, characterized in that the test element (16) has a via an opening of the collecting area (36) acted upon by the body fluid reagent field. 17. Test system for examining body fluids such as blood, comprising a) a collecting element (14) having a microfluidic collecting region (36) for the body fluid, preferably as a semi-open channel, b) a test element (16) which is deflected by deflection of a transfer part (16). 34) of the collecting element (14) with the collecting area (36) for transferring body fluid into fluid communication, and c) a device (10) for inserting at least one collecting element (14) to detect an analyte in the body fluid, characterized in that d) the transfer part ( 34) is biased against a hold-down (20) on the collecting element (14), wherein by releasing the hold-down (20) by means of a device-side trigger (22) the deflection is triggered. 18. Test system according to claim 17, characterized in that the trigger (22) by a non-contact separation unit, in particular a laser (46) is formed. 19. Test system according to claim 17, characterized in that the trigger (22) has a mechanically effective cutting means. 20. Test system according to claim 17, characterized in that the trigger (22) is formed by a thermal actuator. 21. Test system according to one of claims 16 to 20, characterized in that the test element (16) is independent of the collecting element (14) manageable.