A testing device and a method for suppressing nonspecific reactions in immunochromatography.

Abstract

To provide an immunochromatographic device containing a component that can strongly suppress nonspecific reactions without reducing sensitivity, or an immunochromatographic method utilizing said component. [Solution] An immunochromatographic method comprising a membrane having a detection site on which a substance to be detected, which is an antibody or antigen capable of capturing a substance to be detected in a sample, is immobilized, and a label that specifically binds to the substance to be detected, which is an antigen or antibody, is used to form a complex of substance to be detected-substance-substance by antigen-antibody reaction on the detection site on the membrane on which the substance to be detected is immobilized, thereby detecting the substance to be detected by the presence of the label at the detection site by the label, wherein nonspecific reactions are suppressed by including a polyamine in the antigen-antibody reaction system.

Description

Technical Field

[0001] The present invention relates to a technique for strongly suppressing non-specific reactions that could not be completely suppressed by conventional methods by including polyamine in a reaction system when detecting a detected substance such as a virus, bacterium, or protein to be detected from a specimen derived from a body fluid such as a nasal swab specimen, nasal aspirate specimen, nasal wash specimen, nasal mucus specimen, throat swab specimen, saliva specimen, fecal specimen, serum specimen, plasma specimen, urine specimen, etc. using an immunochromatography method (immunochromatography) that utilizes an antigen-antibody reaction.

Background Art

[0002] In recent years, immunochromatography test reagents and kits for detecting the presence or absence of pathogen infections such as viruses and bacteria, pregnancy, etc., which utilize an antigen-antibody reaction, have been continuously developed.

[0003] In recent years, regarding clinical diagnostic agents including immunochromatography, it has been desired from the clinical field that the diagnostic results be more reliable, and further improvement in the reliability of the reagents has become an issue. A highly reliable test reagent is a test reagent with high sensitivity and specificity that is less likely to cause misjudgment. Particularly regarding specificity, there has always been a technical issue of how to deal with the diversity of specimen components derived from differences in the background of each patient in reagent design, and more effective elimination of non-specific reactions is an extremely important issue in simple test methods such as immunochromatography. In order to solve these issues, it has been reported that contacting a specimen with basic amino acids such as arginine and lysine, inorganic salts, glycine ethyl ester, surfactants, animal-derived immunoglobulins, etc. has a certain effect on improving specificity (see Patent Documents 1, 2, and 3), but all of them have limited effects and there are still non-specific reactions that cannot be suppressed. Therefore, a technique that can more strongly improve specificity without reducing sensitivity is desired.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-279577 [Patent Document 2] Japanese Patent Publication No. 2005-24323 [Patent Document 3] Japanese Patent Publication No. 2004-301684 [Overview of the project] [Problems that the invention aims to solve]

[0005] In immunochromatographic methods utilizing antigen-antibody reactions to detect viruses, bacteria, and target proteins from bodily fluid samples such as nasal swab samples, nasal aspirate samples, nasal lavage samples, nasal discharge samples, pharyngeal swab samples, saliva samples, stool samples, serum samples, plasma samples, and urine samples, nonspecific reactions such as false positives and false negatives, which could not be completely suppressed by conventional methods, still exist and hinder accurate diagnosis. This invention provides a test reagent containing a component that can strongly suppress nonspecific reactions without reducing sensitivity. [Means for solving the problem]

[0006] The inventors of the present invention have diligently searched for a method to more strongly suppress nonspecific reactions that occur when using samples derived from bodily fluids, such as nasal swab samples, nasal aspirate samples, nasal lavage samples, nasal discharge samples, pharyngeal swab samples, saliva samples, stool samples, serum samples, plasma samples, and urine samples, as test samples in immunochromatography. As a result, they have discovered a compound that can suppress nonspecific reactions more significantly than conventional methods, and have found that by including this compound in the reaction system, nonspecific reactions that were detected by conventional methods can be suppressed, thus completing the present invention.

[0007] In other words, the present invention is as follows. [1] An immunochromatographic testing device comprising a sample addition pad and a porous detection site having a solidified detection site on which a substance to be detected, which is an antibody or antigen capable of capturing a substance to be detected in a sample, is immobilized, wherein a label that specifically binds to the substance to be detected, which is an antigen or antibody, is used to form a complex of the substance to be detected-substance-substance-label by an antigen-antibody reaction on the detection site on which the substance to be detected is immobilized, and the substance to be detected is detected by the presence of the label at the detection site, wherein the sample addition pad and / or the detection site on the porous membrane contains a polyamine. [2] The immunochromatographic testing device according to [1], wherein the porous detection site contains a polyamine. [3] An immunochromatographic method comprising a sample addition pad and a porous membrane having a detection site on which a substance to be detected, which is an antibody or antigen capable of capturing a substance to be detected in a sample extract, is immobilized, wherein a label that specifically binds to the substance to be detected, which is an antigen or antibody, is used to form a complex of the substance to be detected-substance-substance-label by an antigen-antibody reaction on the detection site on which the substance to be detected is immobilized, and the substance to be detected is detected by the presence of the label at the detection site, wherein the sample addition pad and / or the detection site on the porous membrane contain a polyamine. [4] The immunochromatographic method according to [3], wherein a polyamine is included in the detection site on a porous membrane. [5] The immunochromatographic method described in [3], wherein the specimen is selected from the group consisting of pharyngeal swab specimens, nasal swab specimens, nasal aspirate specimens, pharyngeal lavage specimens, nasal lavage specimens, nasal discharge specimens, saliva specimens, serum specimens, plasma specimens, whole blood specimens, stool specimens, stool suspension specimens, and urine specimens. [6] The immunochromatographic method described in [4], wherein the specimen is selected from the group consisting of pharyngeal swab specimens, nasal swab specimens, nasal aspirate specimens, pharyngeal lavage specimens, nasal lavage specimens, nasal discharge specimens, saliva specimens, serum specimens, plasma specimens, whole blood specimens, stool specimens, stool suspension specimens, and urine specimens. [7] Any immunochromatographic method according to any one of [3] to [6], wherein the polyamine is at least one selected from the group consisting of ethylenediamine, diaminobutane, spermidine, piperazine and spermine. [Effects of the Invention]

[0008] According to the present invention, nonspecific reactions occurring in detection reagents that detect specific viruses, bacteria, proteins, low molecular weight compounds, etc., using immunochromatography based on antigen-antibody reactions from body fluid-derived specimens such as nasal swab specimens, nasal aspirate specimens, nasal lavage specimens, nasal discharge specimens, pharyngeal swab specimens, saliva specimens, stool specimens, serum specimens, plasma specimens, and urine specimens can be more strongly suppressed, and a highly reproducible and highly accurate detection reagent can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the structure of an immunochromatographic testing device. [Modes for carrying out the invention]

[0010] The present invention will be described in detail below. The present invention provides a method for accurately measuring a substance to be detected in an immunochromatographic method by including a polyamine in the antigen-antibody reaction system, thereby suppressing nonspecific reactions. Here, "including a polyamine in the antigen-antibody reaction system" means that the polyamine is present when the antigen-antibody binding reaction occurs, or that the antigen-antibody reaction occurs in the presence of a polyamine. Nonspecific reactions refer to false positives and false negatives, preferably false positives.

[0011] The immunochromatographic method can be performed using an immunochromatographic testing device comprising: a membrane, which is a support having a detection site on which a substance to be detected, such as an antibody (referred to as antibody 1 in the case of an antibody), is immobilized; a label pad, which has a label (referred to as antibody 2 in the case of an antibody), which is a substance that binds to the substance to be detected and is a mobile substance that specifically binds to the substance to be detected, such as a colored polystyrene particle or a suitable labeling substance such as gold colloid; a sample addition pad, to which a sample solution that may contain the substance to be detected is dropped; and an absorption pad, which absorbs the sample solution that has been spread on the membrane. In this method, a liquid containing the prepared substance to be detected is dropped onto the sample addition pad, and the complex of the substance to be detected and the label (a substance that specifically binds to the substance to be detected, such as a colored polystyrene particle or a suitable labeling substance such as gold colloid) is spread and moved on the membrane on which the substance to be detected is immobilized, using capillary action. As a result, a complex of an immobilized substance-capturing agent, the substance to be detected, and a labeled substance that specifically binds to the labeled substance is formed on the detection site on the membrane, and the substance to be detected is detected by the presence of the labeled substance. That is, the substance to be detected can be detected by detecting the signal of the labeled substance emanating from the complex, which originates from the coloring caused by the labeling reagent (in the case of gold colloid, the detection site on the membrane on which the substance that can bind to the antigen to be detected is immobilized turns red). The substance to be detected is either an antigen or an antibody, and an antigen-antibody reaction forms a complex of an immobilized substance-capturing agent, the substance to be detected, and a labeled substance that specifically binds to the labeled substance. When the substance to be detected is an antigen, the substance-capturing agent that captures the substance to be detected is an antibody (antibody 1), and the labeled substance that specifically binds to the substance to be detected is also an antibody (antibody 2), which is a mobile substance that is labeled with a suitable labeling agent such as colored polystyrene particles or gold colloid. If the substance to be detected is an antibody, then a substance that captures the antibody (the substance to be detected) and a substance that specifically binds to the antibody (the substance to be detected) can be used.

[0012] The immunochromatographic testing device will be described in more detail below, based on Figure 1. The following description focuses on immunochromatographic testing devices that detect antigens using antibodies (substances that capture the target substance) immobilized on a membrane and labeled antibodies (substances that specifically bind to the target substance). Note that immunochromatographic testing devices are sometimes also called immunochromatographic test strips or immunochromatographic measurement strips.

[0013] The membrane is a portion of a substrate that has the ability to immobilize antibodies for binding to and capturing the substance to be detected (antigen), and also has the ability not to hinder the horizontal flow of liquid. Preferably, it is a porous thin film with capillary action, and is a material that can transport liquid and components dispersed therein by absorption. The material that makes up the support is not particularly limited, and examples include cellulose, nitrocellulose, cellulose acetate, polyvinylidene difluoride (PVDF), glass fiber, nylon, and polyketone. Of these, a thin film made using nitrocellulose is more preferred. The membrane is sometimes called the development portion, support, or carrier. A membrane with immobilized antibodies is called an antibody-solid-phase membrane or antibody-immobilized membrane.

[0014] The labeled pad 2, also called the labeled region, contains a labeled substance that binds to the substance to be detected. Here, the labeled substance refers to a second substance-capturing substance, such as a mobile antibody labeled with a labeling substance. The labeled substance is preferably a labeled antibody. The labeling substance used for labeling the labeled substance can be selected from the group consisting of gold colloid, platinum colloid, colored polystyrene particles (also called colored latex particles), fluorescent polystyrene particles, colored magnetic particles, colored silica particles, fluorescent silica particles, colored cellulose particles, fluorescent cellulose particles, fluorescent dye labeling, enzyme labeling, or a combination of two or more of these. Labeling can be carried out by known methods.

[0015] The detection site 3, also referred to as the detection region, refers to a partial region on the membrane 1 to which an antibody that binds to and captures the detected substance (antigen) is immobilized. The detection site 3 is a region where an antibody for capturing the antigen is immobilized, and at least one is provided on the membrane 1. The detection site 3 only needs to be included on the membrane 1, and the antibody may be immobilized on the membrane 1.

[0016] Note that the number of detection sites 3 and the types of labeled antibodies included in the labeled body region are not limited to one, and by using antibodies corresponding to a plurality of measurement targets, two or more antigens can be detected with the same immunoassay chromatographic test device. In FIG. 1, there are two detection sites 3.

[0017] The sample addition pad 4, also called the sample pad, is a site for supplying a sample specimen that may contain the detected substance, and is a porous material. Generally used filter paper, glass fiber, non-woven fabric, etc. can be used for this material. In order to use a large amount of sample specimen for immunoassay, it is preferably in the form of a pad with a thickness of about 0.2 mm to 5 mm. The specimen can also include samples obtained by suspending the specimen in other solutions, etc., and samples prepared using the specimen. The supply of the sample specimen may be performed, for example, by dropping. The sample addition pad is also called the sample supply site.

[0018] The absorption pad 5, also called the absorption zone, is a member for absorbing the sample developed on the membrane 1 and the labeled body that did not participate in the reaction. Generally, highly water-retaining filter paper, sponge, etc. made of natural polymer compounds, synthetic polymer compounds, etc. can be used for this material, but those with high water absorption are preferred for promoting the development of the specimen. The absorption pad is also called the sample absorption pad.

[0019] The backing sheet 6 is a member for attaching and fixing all of the aforementioned materials, namely the membrane 1, the sample addition pad 4, the label pad 2, the absorption pad 5, etc., with partial overlap. The backing sheet 6 is not necessarily required as long as these materials are arranged and fixed at an optimal interval, but it is generally preferable to use it for manufacturing or convenience in use. The backing sheet 6 is preferably made of plastic.

[0020] The immunoassay chromatographic test device of the present invention may further have a control display portion. The control display portion is a site indicating that the test has been accurately performed. For example, the control display portion is present downstream of the detection site 3, and when the specimen sample passes through the detection site 3 and reaches the control display portion, it emits a signal by coloring or the like. Substances that bind to the label may be immobilized on the control display portion, or reagents such as pH indicators that change color when the specimen sample arrives may be immobilized. When the antibody bound to the label is a mouse monoclonal antibody, an anti-mouse IgG antibody may be used.

[0021] In the immunoassay chromatographic test device of the above form, the specimen passes through a porous flow path formed by a series of connections such as the sample addition pad 4, the label pad 2, the membrane 1, the detection site 3, the absorption pad 5, etc. Therefore, in this form, all of these become the specimen movement region.

[0022] The size of the immunoassay chromatographic test device is not limited, but for example, the vertical length is several cm to a dozen or so cm, and the horizontal length is about several mm to several cm.

[0023] The entire immunoassay chromatographic test device may be covered with a transparent plastic laminate.

[0024] The immunoassay chromatographic test device may be placed in a container. This container is called a test device case.

[0025] The measurement of substances to be detected using an immunochromatographic testing device can be performed at 5 to 35°C, preferably at room temperature, and pretreatment with a sample processing solution should also be carried out within this temperature range.

[0026] When manufacturing the above-described immunochromatographic testing device, a substance to capture the substance to be detected, such as an antibody, is immobilized on the detection site 3 on the membrane 1. Methods for immobilizing the substance to capture the substance on the membrane 1 include known methods such as physical adsorption or chemical bonding. Specifically, a solution containing the substance to capture is applied to a support and dried to immobilize the substance and form the detection site 3. While the substance to capture is immobilized in a linear fashion on the membrane 1 to form the detection site 3, the shape of the detection site 3 is not limited to a linear shape; it can be circular, rectangular, or any other shape. In this invention, regardless of shape, the area on the support where the substance to capture is immobilized is referred to as the detection site 3.

[0027] When detecting a substance to be detected using an immunochromatographic testing device, the sample containing the substance to be detected is added to the absorbent pad. In this case, the sample may be diluted with a sample extraction solution before being added. The sample extraction solution is also called a sample diluent. In this invention, the immunochromatographic testing device may be called an immunochromatographic testing reagent or an immunochromatographic testing kit, but the terms "immunochromatographic testing reagent" or "immunochromatographic testing kit" also include those containing both the immunochromatographic testing device and the sample extraction solution.

[0028] The specimens used in this invention are not limited. For example, specimens include pharyngeal swabs, nasal swabs, nasal aspirates, pharyngeal lavage solutions, nasal lavage solutions, nasal discharge, saliva, serum, plasma, whole blood, stool, stool suspension, urine, and culture media. These are referred to as pharyngeal swab specimens, nasal swab specimens, nasal aspirate specimens, pharyngeal lavage specimens, nasal lavage specimens, nasal discharge specimens, saliva specimens, serum specimens, plasma specimens, whole blood specimens, stool specimens, stool suspension specimens, urine specimens, and culture media specimens. The method of collecting specimens is also not limited, but examples include collecting specimens using specimen collection devices such as cotton swabs, collecting specimens by spraying lavage solutions into the nasal cavity, collecting specimens using suction devices, and collecting specimens using blood collection tubes. These specimens can be used diluted with a specimen extraction solution or used as is without dilution.

[0029] As the sample extraction solution, buffers commonly used in immunological tests can be used, such as Tris buffer, phosphate buffer, and Good's buffer. Sodium chloride, surfactants, bovine serum albumin, sodium azide, amino acids, etc., may be added as appropriate, but are not limited to these. Examples of surfactants include nonionic surfactants such as polyoxyethylene octylphenyl ether, polyoxyethylene myristyl ether, polyoxyethylene distylenide phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl ether, polyoxyethylene octyldodecyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene tripenzylphenyl ether, polyoxyethylene polyoxypropylene glycol, polyoxyethylene glyceryl ether, and polyoxyethylene diglyceryl ether. Examples of amino acids include L-arginine.

[0030] In this invention, when detecting a substance to be detected using an immunochromatographic testing device, a polyamine is included in the antigen-antibody reaction system.

[0031] There are two methods for adding polyamines: (1) When immobilizing an antibody or other substance to be detected on the detection site 3 on the membrane 1, a polyamine is added to the solution containing the substance to be detected. (2) Add polyamine to the sample dosing pad 4. In case (1), the detection site on the porous membrane contains polyamine.

[0032] In either case, by adding a sample diluted with a sample extraction solution to the immunochromatographic testing device, polyamines are present at the detection site when the substance to be detected reacts with the immobilized antibody or antigen, thereby suppressing nonspecific reactions.

[0033] Examples of polyamines used in the present invention include ethylenediamine, diaminobutane, spermidine, piperazine, spermine, hexanediamine, diaminopropane, and diaminopentane. At least one of these polyamines is included in the reaction system. Multiple of these compounds, for example, two, three, four, or five types, may also be included.

[0034] The amount of polyamine to be included in the antigen-antibody reaction system is (1) when immobilizing the substance to be detected, such as an antibody, on the detection site on the membrane, if polyamine is included in the detection site, then one detection site of one test device is 1 cm². 2 The sample should contain 10 to 10,000 μg, preferably 50 to 5,000 μg, and more preferably 100 to 2,000 μg per unit area. Also, (2) if the sample docking pad contains polyamine, the sample docking pad of one test device should contain 1 cm² 2 The amount should be 10 to 20,000 μg per unit, preferably 100 to 20,000 μg, and more preferably 500 to 6,000 μg.

[0035] The substances to be detected using the immunochromatographic testing device of the present invention are not limited, and any substances that can be detected by antigen-antibody reactions are included. Specific examples include viral antigens such as influenza virus, adenovirus, respiratory syncytial (RS) virus, human metapneumovirus (hMPV), hepatitis A virus (HAV), hepatitis B virus (HBV), human immunodeficiency virus (HIV), norovirus, and coronaviruses such as SARS-CoV, MERS-CoV, and SARS-CoV-2; bacterial antigens such as methicillin-resistant Staphylococcus aureus (MRSA), Group A Streptococcus, Group B Streptococcus, Legionella, and Helicobacter pylori; toxins produced by bacteria; mycoplasma antigens such as Mycoplasma pneumoniae; chlamydia antigens such as Chlamydia trachomatis; protozoan antigens; fungal antigens; hormones such as human chorionic gonadotropin; proteins such as C-reactive protein, myoglobin, cardiac troponin, and procalcitonin; various tumor markers; and antigens such as pesticides and endocrine disruptors. Furthermore, antibodies against the above-mentioned bacteria and viruses can also be listed. [Examples]

[0036] The present invention will be specifically described by the following embodiments, but the present invention is not limited to these embodiments. In the following examples, % indicates w / v% unless otherwise specified.

[0037] 1. Production of RSV monoclonal antibodies BALB / c mice were immunized with RSV antigen, and after being reared for a certain period, their spleens were removed and fused with mouse myeloma cells (P3×63) using the method of Keller et al. (Kohleretal., Nature, vol, 256, p495-497 (1975)). The resulting fused cells (hybridomas) were maintained in a 37°C incubator, and cell purification (monoclonalization) was performed while confirming the antibody activity of the supernatant using ELISA with a plate immobilized with RSV antigen. Two of these cell lines were administered intraperitoneally to pristane-treated BALB / c mice, and approximately two weeks later, antibody-containing ascites fluid was collected. IgG was purified from the obtained ascites fluid by affinity chromatography using a protein A column, yielding two types of purified anti-RSV antibodies.

[0038] 2. Preparation of the label pad One type of purified anti-RSV antibody was used. The anti-RSV antibody was covalently bound to red latex particles, suspended in a suspension solution, and thoroughly dispersed by sonication to prepare an anti-RSV antibody-conjugated latex suspension. The anti-RSV antibody-conjugated latex suspension was coated onto glass fibers and thoroughly dried under warm air to form a labeled pad containing a dried mixture.

[0039] 3. Preparation of the sample dosing pad A non-woven fabric measuring 2.0cm x 20cm was used.

[0040] 4. Fabrication of the testing device The testing device used had a configuration similar to that shown in Figure 1. An anti-RSV antibody solution (a different antibody from the one mentioned above) was applied and thoroughly dried under warm air to immobilize the antibody (detection site). The immobilized nitrocellulose membrane was backed with a plastic plate coated with adhesive. Next, filter paper was placed on top of the upper end of the nitrocellulose membrane to create an absorption pad. Furthermore, a label pad was placed on top of the lower end of the nitrocellulose membrane, and then a sample addition pad was placed on top of the lower end of the label pad to create a sample addition section. Subsequently, the device was cut into strips with a cutter to create an integrated testing device.

[0041] 5. Exam The following are examples of each test.

[0042] Test Example 1: Effect of polyamine-added solid-phase solution on suppressing nonspecific reactions in immunochromatographic detection of RSV antigen. 1-1. Fabrication of a testing device composed of an antibody-solid nitrocellulose membrane A test device consisting of a membrane coated with a solid phase solution containing anti-RSV antibodies and then dried was designated as control 1. Next, a test device consisting of a membrane coated with a solid phase solution containing polyamines shown in Table 1 in addition to anti-RSV antibodies was designated as test device 1.

[0043] [Table 1]

[0044] 1-2. Test Method A false positive reaction was observed in the control 1 testing device. Frozen, RSV antigen-negative nasal aspirates were thawed, and samples were collected using cotton swabs. These samples were suspended and dispersed in a sample extraction solution to prepare the samples for this test. Next, these samples were dropped onto the test device 1 prepared above, and the color intensity of the detection site was measured after 10 minutes. The color intensity was measured using a color chart with points assigned to 10 levels of color intensity.

[0045] 1-3. Results of color intensity test The results are shown in Table 2. The color intensity values ​​increase in the order of 0, 1+, 2+...10+, with 0 indicating no color development and higher values ​​indicating a stronger signal. The results are displayed as "Color Intensity of RSV Antigen Detection Site". While nonspecific reactions were observed in the control solid-phase solution, nonspecific reactions were suppressed in all samples using Test Device 1 with a polyamine-containing solid-phase solution.

[0046] [Table 2]

[0047] Test Example 2: Effect of polyamine-impregnated sample pads on suppressing false positives in immunochromatographic detection of RSV antigen. 2-1. Fabrication of a testing device using a sample dosing pad impregnated with polyamine. A control device (Control 1) using a sample-adding pad that was not impregnated with any compound was used as the control. Next, a test device (Test 2) was prepared using sample-adding pads impregnated with polyoxyethylene octylphenyl ether and spermidine as shown in Table 3.

[0048] 2-2. Test Method Frozen, RSV antigen-negative nasal aspirates, which showed a false positive reaction with control device 1, were thawed, and samples were collected using cotton swabs. These samples were suspended and dispersed in a sample extraction solution to prepare the samples for the main test. Next, these samples were dropped onto control device 1 and test device 2, and the color intensity of the detection site was measured after 10 minutes. Color intensity was measured using a color chart with points assigned to 10 levels of color intensity.

[0049] 2-3. Results of color intensity test The results are shown in Table 3. The color intensity values ​​increase in the order of 0, 1+, 2+...10+, with 0 indicating no color development and higher values ​​indicating a stronger signal. The results are displayed as "Color Intensity of RSV Antigen Detection Site". False positive reactions were observed with Control Device 1, but false positive reactions were suppressed in all samples with Test Device 2 containing spermidine.

[0050] [Table 3] [Industrial applicability]

[0051] The immunochromatographic testing device of the present invention can be used to suppress false positives and detect substances with high sensitivity. [Explanation of Symbols]

[0052] 1 Membrane 2. Label pad 3. Detection site (site on which the antibody is immobilized) 4. Sample Addition Pad 5 Absorbent pads 6 Backing Sheets

Claims

1. An immunochromatographic testing device comprising a sample addition pad and a porous membrane having a detection site on which a substance to be detected, which is an antibody or antigen capable of capturing a substance to be detected in a sample, is immobilized, wherein a label that specifically binds to the substance to be detected, which is an antigen or antibody, is used to form a complex of the substance to be detected-substance-substance-label by an antigen-antibody reaction on the detection site on the membrane on which the substance to be detected is immobilized, and the substance to be detected is detected by the presence of the label at the detection site, wherein the sample addition pad and / or the detection site on the porous membrane contains a polyamine.

2. The immunochromatographic inspection device according to claim 1, wherein the detection site on a porous membrane contains a polyamine.

3. An immunochromatographic method comprising a sample addition pad and a porous membrane having a detection site on which a substance to be detected, which is an antibody or antigen capable of capturing a substance to be detected in a sample extract, is immobilized, wherein a label that specifically binds to the substance to be detected, which is an antigen or antibody, is used to form a complex of the substance to be detected-substance-substance-label by an antigen-antibody reaction on the detection site on the membrane on which the substance to be detected is immobilized, and the substance to be detected is detected by the presence of the label at the detection site, wherein the sample addition pad and / or the detection site on the porous membrane contain a polyamine.

4. The immunochromatographic method according to claim 3, wherein a polyamine is included in the detection site on a porous membrane.

5. The immunochromatographic method according to claim 3, wherein the specimen is selected from the group consisting of pharyngeal swab specimens, nasal swab specimens, nasal aspirate specimens, pharyngeal lavage specimens, nasal lavage specimens, nasal discharge specimens, saliva specimens, serum specimens, plasma specimens, whole blood specimens, stool specimens, stool suspension specimens, and urine specimens.

6. The immunochromatographic method according to claim 4, wherein the specimen is selected from the group consisting of pharyngeal swab specimens, nasal swab specimens, nasal aspirate specimens, pharyngeal lavage specimens, nasal lavage specimens, nasal discharge specimens, saliva specimens, serum specimens, plasma specimens, whole blood specimens, stool specimens, stool suspension specimens, and urine specimens.

7. The immunochromatographic method according to any one of claims 3 to 6, wherein the polyamine is at least one selected from the group consisting of ethylenediamine, diaminobutane, spermidine, piperazine, and spermine.

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