Test device for analyzing body fluids

Abstract

A test instrument for analyzing body fluids such as blood or urine. The instrument includes a wound test tape which can be transported from a storage space into a waste space by advancing the tap. The test tape has a plurality of test sections to which body fluid can be applied at a receiving position and also includes a measuring unit for detecting a constituent of the body fluid on an active test section. In order to carry out auxiliary instrument functions, in addition to the test sections, the test tape has one or more functional sections which can be brought into a functional position by advancing the tape.

Claims

1. A test instrument for analyzing body fluids, comprising: a test tape that can be transported from a storage space to a waste space by advancing the tape, the test tape having a plurality of test sections to which body fluid can be applied at a receiving position, the test sections comprising a reagent which reacts with the body fluid to produce a response to a constituent in the body fluid; a measuring unit for detecting the constituent of the body fluid on an active one of the test sections, wherein the measuring unit comprises an optical measuring unit; the test tape comprising a functional section for an auxiliary instrument function, the functional section being moveable to a functional position by advancing the test tape, wherein the functional section includes a calibration field for calibrating the measuring unit, the calibration field including a white, black, grey, colored or transparent calibration field; and wherein the measuring unit further comprises a comparator configured to compare a measured value detected on the calibration field with a target value resident in the instrument.

2. The test instrument of claim 1 wherein the functional section comprises a plurality of functional sections comprising a calibration field, the test sections and functional sections comprising a calibration field alternating along the lengthwise direction of the tape.

3. A test instrument for analyzing body fluids, comprising: a test tape that can be transported from a storage space to a waste space by advancing the tape, the test tape having a plurality of test sections to which body fluid can be applied at a receiving position, the test sections comprising a reagent which reacts with the body fluid to produce a response to a constituent in the body fluid; a measuring unit for detecting the constituent of the body fluid on an active one of the test sections, wherein the measuring unit comprises an optical measuring unit; the test tape comprising a functional section for an auxiliary instrument function, the functional section being moveable to a functional position by advancing the test tape, wherein the functional section includes a calibration field for calibrating the measuring unit, the calibration field including a white, black, grey, colored or transparent calibration field; and wherein the measuring unit further comprises a comparator configured to compare a value measured on the calibration field with a target value.

4. The test instrument of claim 3, wherein the functional section comprises a plurality of functional sections and the test sections and functional sections alternate along the lengthwise direction of the test tape.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The above-mentioned aspects of the present invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of the embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 shows a portable blood sugar measuring instrument for diabetics with a test tape in a simplified sectional view; and

(3) FIG. 2 shows the test tape with test sections and additional functional sections in a partial perspective view.

(4) Corresponding reference characters indicate corresponding parts throughout the several views.

DETAILED DESCRIPTION

(5) The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.

(6) The blood sugar measuring instrument 10 shown in FIG. 1 comprises an instrument housing 12, a tape cassette 14 with a test tape 16 that is inserted therein and an optical measuring unit 18 for analyzing blood applied to the test tape. The measuring unit 18 is coupled with a guide tip 19 in the area of a blood receiving position 20 for the targeted application of a drop of blood on the test tape. The general principle of the instrument is described in detail in the EP Application No. 02026242.4 to which reference is made and the contents thereof are herewith incorporated.

(7) The tape cassette 14 has a cassette housing 22 with a storage chamber 24 for a supply spool 26 and a storage chamber 28 for a take-up or waste spool 30. A spool drive 32 enables the test tape 16 to be advanced in sections from the storage spool 26 onto the take-up spool 30. The part of the test tape 16 that runs free between the spools 26, 30 is guided over deflection rollers 34 and over the guide tip 19.

(8) As can also be seen in FIG. 2, the test tape 16 has a continuous carrier foil 36 which is provided with test sections 38 for analytical purposes and additional functional sections 40 for the auxiliary instrument functions. The carrier foil 36 consists of a polymer foil of approximately 20 m thickness which is, for example, made of polyester.

(9) Reagent fields are applied in the area of the test sections 38 for example by gluing or labelling methods using prefabricated test elements or by means of direct coating methods and in particular printing methods. The reagent fields contain dry chemicals which respond with a color change to the analyte (glucose) in the applied blood fluid. This reaction is detected by a reflection-photometric measurement carried out by the measuring unit 18. In this connection, the measuring unit 18 is optically coupled via the guide tip 19 designed as a light guide and through the transparent carrier foil 36 to a section of test tape 38 which is at that moment active and located in the receiving position 20. The test sections 38 can be successively brought into use by an appropriate tape advance. In this manner it is possible to automatically carry out a plurality of tests for patient self monitoring without having to replace consumables.

(10) During the tape transport the functional sections 40 also reach their respective functional position. In this connection an interaction with the measuring unit 18 may be provided as shown in FIG. 1. The functional sections 38 may alternatively or additionally have additional functions with regard to other instrument components or the user.

(11) In the embodiment shown, the functional sections 40 are alternately applied with the test sections in the direction of tape movement (in the lengthwise direction of the test tape) and are applied to the carrier foil 36 on the same side of the tape as the tape sections by printing or gluing or by other suitable measures. Other arrangements are also conceivable, depending on the respective function, such as only at the start of the test tape 16 or on the rear side of the tape facing away from the blood application side.

(12) In order to calibrate the optical measuring unit 18, the functional sections 38 can be formed by a calibration field with defined optical properties. White, black, grey or coloured fields can be used for this purpose. The calibration can compensate for aging or other change between the time the tape was manufactured and the time of use to thus ensure accuracy of measurement. Colored fields can be used for wavelength control or for drift correction, for example, in the case of temperature variations. An area of the transparent carrier foil 36 which reflects almost no light may already be sufficient for the dark calibration. The target values of the calibration fields are expediently fed into the instrument 10 in a batch-specific manner, e.g., by means of a functional field 40 as a coding or storage medium which interacts with an evaluation unit that is not shown.

(13) The measuring unit 18 is calibrated by means of a comparator 42 by comparison with a target value or characteristic field that is deposited in the instrument. The adjustment of the measuring unit 18 also enables a very accurate control of the blank value on an unused test section 38. This allows a very sensitive detection of a discoloration or other change that indicates unusability.

(14) A cleaning function can be achieved by applying a functional field 40 made of a soft material such as felt or paper on the rear side of the carrier tape 36 facing the measuring unit 18. When the tape is advanced, this cleaning field glides over the measuring window and thus automatically removes dirt and dust without requiring additional instrument or user interventions.

(15) In the resting state the optical system of the measuring unit 18 is hardly protected by the thin transparent carrier tape 36. As a remedy, a functional section 40 that is suitable as a protective field can be located in front of the optical system in the resting position in order to improve screening against environmental influences. An elastic flat piece of material is, for example, suitable for this. Such a protective field can also be guided more reliably, thus preventing it from sliding off sideways from the guide tip 19.

(16) Another application of the functional sections 40 is for fields that change color in a temperature-dependent manner to act as sensors for the current temperature or the temperature during storage and optionally indicate that a temperature has been exceeded. A moisture-sensitive functional field could also be provided to warn against unsuitable conditions.

(17) A metal foil as a functional section 40 on the carrier tape 36 and an approximation switch in the instrument 10 could trigger start and stop signals or control an instrument flap. Metal foils of different resistances can be read electrically. A magnetizable piece of foil could be read and also written.

(18) In addition, the functional sections may contain information that can be directly read by the user, such as an alpha or numeric character that indicates the number of test sections 38 that are still available, i.e., unused. This would allow the user to read the number of remaining stock even on a cassette 14 removed from the instrument 10. A colored, e.g. red, warning field positioned before the last few test sections 38 on the tape could make the user aware that the tape will be depleted soon.

(19) Another additional function is for an absorbent functional field 40 to take up an excess of blood sample so that it can dry hygienically in the waste chamber 28. A functional field containing a preservative could if required further improve the hygiene in the waste chamber 28.

(20) The functional field 40 may also simultaneously provide several auxiliary functions. For example, a somewhat thicker white paper field can be used for calibration, cleaning and protection. The beginning of this field cleans after the measurement. The middle part is in front of the lens system during the period of non-use and protects it. The current test number is printed visibly for the user on the middle part. The end part is used before the new measurement to calibrate the optical system. Excess blood is taken up in the waste chamber 28 which improves the hygiene.

(21) Having described several advantageous embodiments above, one of skill in the art can now readily appreciate that exemplary embodiments of the present invention provide a test tape that not only includes test sections which are typically used to detect or determine concentration of a constituent in a body fluid, but also provides functional sections that can perform one or more of a variety of auxiliary functions.

(22) While exemplary embodiments incorporating the principles of the present invention have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.