Lancet magazine and method for the production thereof

Abstract

A lancet magazine is disclosed which includes a housing and a plurality of lancets each of which is enclosed in a sterile chamber of the housing, wherein the chambers each have a puncturing opening which is closed with a foil, wherein the lancets include a sample receiving device for receiving body fluid and the chambers each include a further opening which is closed with a membrane that is permeable to gas and fluid and includes a lower side that faces the lancet and serves to receive body fluid from the sample receiving device and an upper side that serves to transfer body fluid to a test field arranged on the membrane.

Claims

1. A method comprising: transporting a body fluid sample from a lancet on one side of a membrane to a test field on the other side of the membrane, the step of transporting comprises: contacting the lancet having the body fluid sample with the inner side of the membrane, and delivering the body fluid sample through the membrane to the test field by capillary forces; wherein the membrane is permeable to gas and fluid and is configured to close an opening of a chamber of a lancet magazine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details and advantages of the present disclosure will be illustrated by means of an illustrative embodiment with reference being made to the accompanying drawings. In the drawings,

(2) FIG. 1 shows an illustrative embodiment of a lancet magazine according to the present disclosure;

(3) FIG. 2 shows one half of the magazine shown in FIG. 1 with lancets arranged therein; and

(4) FIG. 3 shows a lancet.

DETAILED DESCRIPTION

(5) FIG. 1 shows a lancet magazine with a plastic housing, for example, made of polycarbonate or polysulphone. In the illustrated illustrative embodiment, the housing is joined together from two housing halves 1a, 1b. The lower housing half 1b is shown in FIG. 2. The housing 1 has a plurality of chambers, with a lancet 2 being arranged in each of said chambers.

(6) An illustrative embodiment of a lancet 2 is shown in FIG. 3. The lancet 2 has a sample receiving device 3 which, in the illustrated illustrative embodiment, is designed as a channel, more precisely a groove. During a puncture into the body tissue of a patient, the channel is filled with blood and/or interstitial fluid by capillary forces. A plurality of channels can be provided one beside the other to increase the sample volume received. The sample receiving device 3 can comprise a hydrophilic coating, for example heparin, in order to achieve a better receiving of the sample.

(7) Optionally, the individual chambers of the housing 1 each have at least three openings, i.e. a puncturing opening 4 with the lancet 2 exiting from said puncturing opening 4 during a puncture, a slide-in opening 5 into which a plunger of a lancet device can be pushed in order to push a lancet 2 forward out of the puncturing opening 4 for a puncturing motion and retract it again, as well as a further opening 6 which is covered by a test field 7. FIG. 1 only shows half of the further openings 6 in covered condition in order to give a better view of the structure of the lancet magazine.

(8) The openings 6 are closed with a fluid-permeable membrane 8 on which the test field 7 is disposed. The membrane 8 has a permeability limit of less than 0.5 m, and optionally 0.2 m. Particles the size of which is in excess of the permeability limit are retained by the membrane 8, whereas smaller particles can pass through said membrane 8. The pores of the membrane 8 form channels extending through the membrane 8. Therein, the relevant pore size is the maximum diameter of the channels at their narrowest point. Optionally, the relevant pore size of the membrane is no more than 5 m, and optionally is no more than 2 m.

(9) Suitable membranes 8 can, for example, consist of fiber material. Apart from paper, materials made of plastic fibers, in particular nonwoven materials, are particularly suitable. DuPont sells a suitable nonwoven material which consists of heat-sealed polyethylene fibers under the trade name of TYVEC. As an alternative to fiber materials, use can also be made of other porous materials, for example foamed plastics or membranes produced according to the phase inversion method. A suitable membrane 8 is, for example, sold by Messrs. Pall GmbH, Dreieich, Germany, under the name of BTS 45. Hydrophilic membranes are particularly suitable.

(10) The other chamber openings, i.e. the puncturing opening 4 and the slide-in opening 5 in the illustrated instance, can actually also be closed with a membrane 8 that is permeable to fluid and, therefore, also to gas. Alternatively, however, the openings 4, 5 are closed with a more cost-effective material, i.e. gas-tight foils (not shown). Plastic films, metal foils and plastic-coated metal foils are particularly suitable.

(11) The first step in the production of the magazine shown in FIG. 1 is arranging the lancets 2 in the magazine chambers. Subsequently, the chamber openings 4, 5 and 6 are closed. Thereafter, the lancets 2 are sterilized by introducing a sterilizing gas through the gas-permeable membrane 8 and into the magazine chambers. For example, the closed magazine can be exposed to 121 C. hot water vapor for 20 minutes. To improve the sterilization effect, further sterilizing gases can be admixed to the water vapor. For example, it is also possible to use ethylene oxide as sterilizing gas, in particular according to DIN EN 550 or EN ISO 11135.

(12) The lancets 2 are disposed in the magazine chambers such that they are exposed, which means that they are in contact with the gas contained in the chambers and, therefore, also with the gas introduced for sterilization. The tips of the lancets 2 and a puncture region 2a which is disposed adjacent to the tips and penetrates into the body of a patient during a puncture, optionally, do not have any contact with the magazine housing 1, with the result that the complete surface of the puncture region 2a is in contact with the gas contained in the chambers and, therefore, also with the gas introduced for sterilization. For this reason, the puncture region 2a can be sterilized by exposure to gas in a particularly fast manner. For example, the lancets 2 can be held in the magazine chambers and rest against magazine walls by means of a lancet body adjacent to the puncture region 2a.

(13) After sterilization, a test field 7 with analytical reagents for the examination of a body fluid sample is applied onto the gas-permeable membrane 8. In the presence of an analyte, for example glucose, the analytical reagents initiate a detection reaction which can be evaluated to determine the searched-for analyte concentration. Optionally, use is made of analytical reagents the detection reaction of which causes the test field to change its color, thus allowing a photometric evaluation such as it is customary with commercially available test strips.

(14) The chamber openings 6 can each be closed with individual membrane platelets. It is, however, easier to cover a plurality, optionally all, of the chamber openings 6 with a single piece of membrane 8. In corresponding manner, individual test fields 7 can be applied onto each of the closed chamber openings 6. It is, however easier to cover a backing film, for example made of transparent plastic, with analytical reagents and to place it onto the membrane 8. If use is made of an impermeable backing film, it must be ensured that the reagent layer on the backing film faces the membrane 8. In one embodiment, the reagent layer rests against the membrane 8 and, therefore, has contact therewith, with the result that a body fluid sample can easily pass over from the membrane 8 into the reagent layer.

(15) So, the membrane that is permeable to gas and fluid has a lower side that faces the lancet 2 and serves to receive body fluid from the sample receiving device 3 and an upper side that serves to transfer body fluid to a test field 7 disposed on the membrane 8. Optionally, the pore size on the lower side of the membrane is in excess of that on the upper side. The increased pore size on the lower side facilitates the passover of body fluid from the lancet into the membrane while the reduced pore size on the upper side makes the penetration of microorganisms and other causative organisms more difficult.

(16) In order to allow a good transfer of the sample from the sample receiving device 3 of a lancet 2 through the membrane 8 and to the test field 7 after a lancet puncture, the reagent layer on the backing film should be designed such that it is relatively smooth. In particular, roughness values SRq of less than 3 m, optionally of less than 2 m, are advantageous. Roughness values SRmax of less than 30 m, and optionally of less than 20 m, are favorable. The specified roughness values SRmax and SRq each refer to measurements with a laser scanning microscope according to DIN EN ISO 25178/(2 and 3) and an adequate image processing filter according to ISO/DIS 16610-21.

(17) The lancet magazine described can be inserted into a magazine compartment of a lancet device that is not shown here, said lancet device comprising a puncturing drive to push a lancet 2 out of the puncturing opening 4 and retract it again. To achieve this, the puncturing drive can comprise a plunger which, while a puncture is made, is pushed into a slide-in opening 5 of a magazine chamber, is coupled to a lancet 2 and pushes the latter out of the puncturing opening. Therein, both a foil closing the slide-in opening 5 and a foil closing the puncturing opening 4 are pierced. In order to facilitate coupling of the puncturing drive to the lancet 2, the latter can comprise a coupling element that is a perforation 2b in the illustrated illustrative embodiment. The puncturing drive has the effect that the sample receiving device 3 of a lancet 2 rests against the membrane 8 at the end of a lancet motion. Once received, a body fluid sample is then received by the membrane 8 by capillary forces and transported therethrough to the test field 7. A suitable puncturing drive can, for example, be implemented as a rotor drive with a link motion. In addition, the lancet device may have a measuring device which, along with test field 7, allows determining a concentration, for example by photometric measurement.

REFERENCE SYMBOLS

(18) 1 Housing 1a Housing half 1b Housing half 2 Lancet 2a Puncture region 2b Perforation 3 Sample receiving device 4 Puncturing opening 5 Slide-in opening 6 Further openings 7 Test field 8 Membrane