TWI701019B - Test strip and optical blood glucose detecting apparatus - Google Patents

Abstract

The invention discloses a test strip and an optical blood glucose detecting apparatus. The test strip comprises a base layer; an intermediate layer overlaid on the base layer; a blood retaining layer comprising a slit and a blood retaining region fluidly commuted with the slit and overlaid on the intermediate layer; an upper layer overlaid on the blood retaining layer; a reagent disposed on a surface of the intermediate layer and exposed to the slit, wherein there are an expected predetermined depth and a measured depth from an interface between the slit and the upper layer to an upper surface of the intermediate layer; and a category mark representing a compensation factor; wherein the compensation factor is the product of a difference between the predetermined depth and the measured depth and a reciprocal of the predetermined depth.

Description

Test strip and optical blood glucose detection device

The present invention relates to a detection strip and an optical blood glucose detection device that can compensate for errors caused by the actual depth variation in a slit of a blood storage layer in the detection strip.

Diabetes is a clinical syndrome caused by factors such as absolute or relative lack of insulin in the body, abnormal secretion time, and disorder or resistance of insulin acting body. If diabetes is not well controlled, it will cause some acute complications, such as hypoglycemia, ketoacidosis, and non-ketone hyperosmolar coma. Serious long-term complications include cardiovascular disease, chronic renal failure, retinopathy, neuropathy and microvascular disease.

For diabetics, it is very important to monitor blood sugar from time to time. The primary goal of managing diabetes is to maintain a normal blood sugar level. If the patient can pay attention to blood sugar control, it will effectively prevent the above complications. At present, most of the blood glucose meters used at home on the market are whole-blood blood glucose tests. For example, the blood glucose concentration is determined by electrochemical or photochemical methods after obtaining the patient's blood with a blood sampling needle and test paper.

Chinese Patent No. CN1099035C discloses a test strip for detecting blood sugar, such as the test strip 10 shown in FIG. 1. A reagent pad 11 with a hydrophilic group is fixed on a surface of a plastic carrier 12 by an adhesive 13, and the plastic carrier 12 has a hole 14 in the part where it adheres to the reagent pad 11. The blood sample is dripped from the hole 14 into the micro-hole in the reagent pad 11 and pressed against a test surface 15. There are reagents in the test pad 11 that can chemically react with glucose in the blood. A light-emitting diode 16 projects light on the test surface 15, and a light detector 17 receives the diffusely reflected light. According to the change in reflectance or reflectance observed by the test surface 15, the glucose value in the blood can be obtained. In order to make the change in reflectance more accurately represent the glucose value, it is even necessary to use different wavelengths of light to complete multiple calibrations before testing. Therefore, the test strip 10 obtains the blood glucose level from the change in reflectance or reflectance, which is not only complicated to calibrate, but also the diffuse reflected light to be received is easily affected by ambient light.

In order to ensure the accuracy of blood glucose measurement, the present invention proposes a blood glucose test strip suitable for automatic correction of test strip classification.

This application provides an optical blood glucose detection device, which can read a classification mark on a detection strip, and adapt to the classification of the detection strip for automatic compensation and correction.

Therefore, the present application provides a test strip, including: a bottom layer; an intermediate layer stacked on the bottom layer; a blood storage layer including a slit and a blood storage area connected to the slit, stacked Placed on the middle layer; a top layer is stacked on the blood storage layer; a reagent is placed on the surface of the middle layer and exposed in the slit, wherein the junction of the slit and the top layer There is an expected predetermined depth and a measured actual depth to the upper surface of the reagent; and a classification mark representing a compensation coefficient; wherein the compensation coefficient is the difference between the predetermined depth and the actual depth multiplied by the predetermined The product of the reciprocal of depth.

In another embodiment, the bottom layer includes an opening, and the opening is aligned with the reagent.

In another embodiment, the bottom layer, the middle layer, and the top layer each include a through hole, and the three through holes are aligned with the blood storage area.

In another embodiment, the classification mark is marked on the upper surface of the top layer or on the lower surface of the bottom layer.

In another embodiment, the predetermined depth is between 40 μm and 50 μm.

The present invention provides another embodiment, an optical blood glucose detection device, which is used to measure the blood glucose level of blood stored in the test strip as described in any one of claims 1 to 6, which includes: a specimen accepts A unit that can accommodate the test strip; a light-emitting unit that emits light to the test strip; a light-receiving unit that detects light that passes through the blood; a classification recognition unit that reads a classification mark on the test strip; and an operation control unit , Perform colorimetric analysis based on the signal generated by the light receiving unit, and compensate the colorimetric analysis error caused by the actual depth variation based on the signal generated by the classification and identification unit.

In another embodiment, the light emitting unit emits light to the blood, and the light receiving unit detects the light passing through the blood that has reacted with a reagent on the test strip.

In another embodiment, the colorimetric analysis is based on a formula of Lambert-Beer law to calculate the concentration of the blood and the reaction product of the reagent.

In another embodiment, the actual depth variation causes a change in the optical path length of the formula, and the arithmetic control unit compensates for errors in the calculated value of the product concentration caused by the change in the optical path length.

10: Test strip

11: Reagent pad

12: Plastic carrier

13: Adhesive

14: Hole

15: Test surface

16: LED

17: Light detector

20: Test strip

21: bottom layer

22: middle layer

23: blood reservoir

24: top floor

25: Classification mark

26: Reagent

50: Optical blood glucose detection device

51: Specimen receiving unit

52: light-emitting unit

53: Light receiving unit

54: Classification recognition unit

55: Operation control unit

56: operating unit

57: display unit

212, 222, 242: through hole

211: Opening

231: slit

232: Blood Storage Area

411: Light-emitting element

421: light receiving element

D’: Actual depth

Figure 1 shows a schematic diagram of a conventional test strip and its optical inspection.

Fig. 2 is a three-dimensional exploded schematic diagram of the test strip of this application.

Fig. 3 is a three-dimensional schematic diagram of the test strip of this application.

Fig. 4 is a schematic diagram showing the test strip of this application along the A-A section line in Fig. 2 and its optical inspection.

Fig. 5 is a block diagram of the optical blood glucose detection device of the present application.

Hereinafter, various embodiments for implementing the present invention will be described. Please refer to the attached drawing and refer to its corresponding description. In addition, in this specification and the drawings, substantially the same or the same configuration will be given the same reference numeral, and repeated description thereof will be omitted.

Fig. 2 is a three-dimensional exploded schematic diagram of the test strip of this application. A test strip 20 includes a bottom layer 21, a middle layer 22, a blood storage layer 23, and a top layer 24. The top layer 24 is a transparent film layer formed by an adhesive material, and the upper surface of the top layer 24 is marked with a classification mark 25 to distinguish the characteristics and classification of the test strip 20. In this embodiment, the classification mark 25 is used to distinguish the actual depth from the boundary between the slit 231 of the blood storage layer 23 and the top layer 24 to the upper surface of a reagent 26 (described in detail later and in FIG. 4). The classification of is not limited to being marked on the upper surface of the top layer 24, and may also be marked on the lower surface of the bottom layer 21, so that the optical blood glucose detection device or optical blood glucose meter can be identified. In this embodiment, the classification mark 25 may be a mark or mark generated by a laser machine or an inkjet printer, for example: a pattern or dot mark or mark of different gray scales marked by a laser machine.

The bottom layer 21 of the test strip 20 can be made of an opaque plastic material, such as a black polyethylene terephthalate (PET) film, which includes openings 211 and through holes 212. The intermediate layer 22 is a transparent film layer, which includes a through hole 222 aligned with the through hole 212. The predetermined thickness of the blood storage layer 23 is preferably 54 μm. The blood storage layer 23 has a slit 231 extending from the outside to the inside, and the blood sampled from the finger of the subject can be introduced into a blood storage area 232 through the slit 231. The top layer 24 can be made of a transparent plastic material, such as a transparent polyethylene terephthalate film layer, which includes through holes 242. In particular, a reagent 26 is attached to the intermediate layer 22 close to the surface of the blood storage layer 23. The reagent 26 is exposed in the slit 231, and The openings 211 of the bottom layer 21 are aligned with each other, and light will pass through the transparent top layer 24 and the middle layer 22 and pass through the reagent 26 and exit from the opening 211. In this embodiment, the blood storage layer 23 is a transparent film layer formed of an adhesive material. However, it is difficult to control because the adhesive material of the blood storage layer 23 or the reagent 26 on the intermediate layer 22 is coated unevenly or contracted. The optical path length in the slit 231 is uniform (that is, the predetermined depth described later), so the classification mark 25 needs to be used to distinguish the actual depth from the boundary between the slit 231 and the top layer 24 to the upper surface of a reagent 26 Different classifications formed by mutations. In addition, the centers of the through holes 212, 222, and 242 of the other group are also aligned with each other, and their center lines pass through the blood storage area 232, that is, communicate with each other. Similarly, optical measurement is used to obtain the red blood cells in the blood. The percentage of the volume (that is, the hemolysis ratio, HCT) can better understand the blood glucose measurement value. Because the blood glucose measurement value is often affected by the hemolysis ratio, the measured hemolysis ratio can be used to correct the blood glucose measurement value. The measurement of the blood cell volume ratio is not the focus of the present invention, so it will not be repeated.

Fig. 3 is a three-dimensional schematic diagram of the test strip of this application. A blood sampling needle (not shown in the figure) is used to take a blood sample from the subject’s finger, and the blood will be introduced into the internal blood storage area 232 through the slit 231, and react with the reagent 26, and the concentration of the reaction product and the blood glucose value become Proportional or a proportional relationship, and change the color of blood, the blood glucose level can be obtained by a colorimetric analysis. It is specifically stated here that the result of colorimetric analysis is directly proportional to the blood glucose value.

Colorimetry (colorimetry) is a very commonly used method in biochemical detection. It uses the Beer-Lambert Law as the basis for calculating the concentration of reaction products. Its formula is expressed as: A=αLC (Formula 1 ) Where A is the light absorption; α is the absorption coefficient; L is the optical path length or the thickness of the absorption layer; C is the concentration of the light-absorbing substance.

Fig. 4 is a schematic diagram showing the test strip of this application along the A-A section line in Fig. 2 and its optical inspection. A light emitting element 411 (for example, a light emitting diode) is aligned with the opening 211 of the bottom layer 21 Light, the light first passes through the opening 211 and the transparent intermediate layer 22, part of the light is absorbed by the blood 80 that has reacted with the reagent 26, and the other part of the light penetrates the blood 80 and reaches the light receiving element 421 through the top layer 24 (For example: photodiode). Theoretically, the thickness of the blood storage area 232 minus the thickness of the reagent 26 is the optical path length of the aforementioned formula 1. If the design of the test strip 20, the predetermined thickness of the blood storage area 232 is 54μm, and the predetermined thickness of the reagent 26 is 4μm, in order to make the colorimetric analysis result acceptable or allowable error range, it needs to be controlled in the optical path The length (that is, the predetermined depth in the slit 231) is equal to 50 μm (ideal design value), otherwise a concentration value exceeding the allowable error will be obtained. However, in the actual manufacturing process, the blood storage layer 23 is connected with the top layer 24 and the middle layer 22 by an adhesive material. It is difficult to control due to the uneven coating of the reagent 26 on the test strip manufacturing process or the shrinkage/squeezing of the upper and lower layers The actual depth D'in the slit 231 is uniform and equal to a predetermined depth (D, not shown in the figure), which affects the optical path length L in the aforementioned formula 1 is very large.

However, the preferred embodiment of the present invention controls the optical path length L to a fixed predetermined depth, that is, 50 μm, but the present invention is not limited to this value. In other embodiments, the predetermined depth may vary according to actual design requirements, for example, the predetermined depth may be between 40 μm and 50 μm. In the actual manufacturing process, first, the actual depth D'in the slit 231 in the plurality of test strips 20 can be quickly measured (for example: optically measuring the thickness of the film layer) through an optical measuring instrument, and the predetermined depth D is compared with the actual depth. The difference of the depth D′ multiplied by the reciprocal of the predetermined thickness D (about 2%) is the compensation coefficient. Then, the compensation coefficients corresponding to the plurality of test strips are marked with the classification mark 25 of different gray levels, so the test strips have different classifications. In short, the classification mark 25 can be used to distinguish the different classifications formed by the actual depth variation in the slit 231 of the blood storage layer 23, so that the error caused by the optical path length variation in formula 1 can be compensated. For example, if the actual depth D'obtained by the measurement is 54μm, the value obtained in formula 1 needs to be compensated by about (50-54)×2%, which is minus 8%. On the contrary, if the actual thickness D is 47μm, the value obtained in formula 1 needs to be compensated by about (50-47)×2%, that is, because the actual depth (the actual optical path length) is less than the predetermined depth, the measured value The blood glucose value is compensated by positive 6%, which is 1.06 times the obtained blood glucose value is the last displayed blood glucose value.

Fig. 5 is a block diagram of the optical blood glucose detection device of the present application. As shown in the figure, an optical blood glucose detection device 50 is used to measure the blood glucose level of blood stored in a test strip. It includes a sample receiving unit 51, a light emitting unit 52, a light receiving unit 53, a The classification recognition unit 54 and an operation control unit 55. The specimen receiving unit 51 accommodates the test strip 20. The light-emitting unit 52 emits light to the detection strip 20, which may include the light-emitting element 411 as shown in FIG. 4. The light receiving unit 53 detects light passing through the blood, and may include the light receiving element 421 as shown in FIG. 4. The classification recognition unit 54 reads the classification mark 25 on the detection strip 20, which can also include a light emitting element for projecting light and a light receiving element for sensing reflected light (not shown). The arithmetic control unit 55 performs the aforementioned colorimetric analysis according to the signal generated by the light receiving unit 53, and compensates the actual depth variation in the slit 231 of the blood storage layer 23 in the test strip 20 according to the compensation coefficient generated by the classification recognition unit 54 Cause the error of the colorimetric analysis. The optical blood glucose detection device 50 further includes an operating unit 56 that can be touched and set by the user, and a display unit 57 that can display the setting value and the measurement result.

The technical content and technical features of the present invention have been disclosed above, but those familiar with the technology may still make various substitutions and modifications based on the teaching and disclosure of the present invention without departing from the spirit of the present invention. Therefore, the protection scope of the present invention should not be limited to those disclosed in the embodiments, but should include various substitutions and modifications that do not deviate from the present invention, and are covered by the following patent applications.

20‧‧‧Test strip

21‧‧‧Bottom

22‧‧‧Middle layer

23‧‧‧Blood Reservoir

24‧‧‧Top floor

25‧‧‧Classification mark

26‧‧‧Reagent

212、222、242‧‧‧Through hole

211‧‧‧Opening

231‧‧‧Slit

232‧‧‧Blood storage area

Claims (7)

A test strip includes: a bottom layer; an intermediate layer stacked on the bottom layer; a blood storage layer including a slit and a blood storage area connected to the slit, stacked on the intermediate layer; A top layer is stacked on the blood storage layer; a reagent is provided on the surface of the middle layer and exposed in the slit, wherein there is a line from the boundary between the slit and the top layer to the upper surface of the reagent Expected predetermined depth and a measured actual depth; and a classification mark, which represents a compensation coefficient, the classification mark is marked on the upper surface of the top layer or the lower surface of the bottom layer; wherein, the compensation coefficient is the predetermined The difference between the depth and the actual depth is multiplied by the product of the reciprocal of the predetermined depth; wherein the bottom layer, the middle layer, and the top layer each include a through hole, and the three through holes are aligned with the blood storage area. The test strip according to claim 1, wherein the bottom layer includes an opening, and the opening is aligned with the reagent. The test strip according to claim 1, wherein the predetermined depth is between 40 μm and 50 μm. An optical blood glucose detection device for measuring the blood glucose level of blood stored in the test strip as described in any one of claims 1 to 3, comprising: a sample receiving unit that can accommodate the test strip; A light emitting unit to emit light to the detection strip; a light receiving unit to detect the light passing through the blood; A classification recognition unit that reads the classification mark on the test strip; and an arithmetic control unit that performs colorimetric analysis based on the signal generated by the light-receiving unit, and compensates for the actual situation according to the compensation coefficient read by the classification recognition unit Depth variation causes errors in the colorimetric analysis. The optical blood glucose detection device according to claim 4, wherein the light emitting unit emits light to the blood, and the light receiving unit detects the light passing through the blood that has reacted with the reagent on the test strip. The optical blood glucose detection device according to claim 5, wherein the colorimetric analysis is based on a formula of Lambert-Beer law to calculate the concentration of the product reacted by the blood and the reagent. The optical blood glucose detection device according to claim 6, wherein the actual depth variation causes a change in the optical path length of the formula, and the calculation control unit compensates for the calculation of the concentration of the product caused by the change in the optical path length The error caused by the value.

Images