Immunodetection test strip capable of avoiding HOOK effect

Abstract

The utility model provides an immunodetection test strip capable of avoiding a HOOK effect. The immunodetection test strip comprises a bottom plate, a sample pad, a combination pad, an NC (nitrocellulose) membrane and a water absorption pad are sequentially arranged on the bottom plate, at least two detection lines and at least one quality control line are arranged on the NC membrane, and a detection line and a quality control line are sequentially arranged on the NC membrane along the chromatography direction of the test paper. The design of the test strip allows rapid detection, the result can be obtained in a short time, the test strip is suitable for on-site rapid screening, the whole detection process is simple, a user only needs to add a sample, and complex operation is not needed. The C line serves as a built-in contrast, the reliability of each test is ensured, and a user can conveniently judge whether the test is effective or not.

Description

Technical Field

[0001] The utility model relates to the technical field of immunochromatography, in particular to an immunodetection test strip for avoiding the HOOK effect. Background Technique

[0002] When the content of the antigen to be detected in the sample is very high, the excessive antigen binds to the gold-labeled antibody and no longer forms a "sandwich complex" with the antibody at the test line position. At this time, if measured and read according to the conventional method, the obtained result will be lower than the actual content. This phenomenon is called the HOOK effect (HOOK EFFECT), because the standard curve shows a hook-shaped drop after reaching the peak. When the HOOK effect is severe, the reaction may not even show color, resulting in a false negative clinical result. When detecting macromolecular proteins by the double antibody sandwich method, if the antigen to be detected is excessive, the "HOOK effect" will occur, and a strongly positive result will be misjudged as negative.

[0003] The fluorescence immunochromatographic test strip and the fluorescence immunochromatographic detection card provided by Patent CN202120196493.6 solve the problem that the linear range of a general fluorescence immunochromatographic test strip is narrow and cannot meet the needs of detecting equine serum amyloid A. In order to improve its linear range, the fluorescence immunochromatographic test strip of the utility model optimizes the position of the test line, so that the distance between the end of the reaction membrane close to the conjugate pad and the test line is 1.35 cm to 1.85 cm, which is beneficial to increasing the linear range of the test strip. However, it does not solve the problem that the "HOOK effect" will occur when the antigen to be detected is excessive and a strongly positive result will be misjudged as negative. Content of the Utility Model

[0004] The technical problem to be solved by the utility model is that the existing "HOOK effect" will occur when the antigen to be detected is excessive, and a strongly positive result will be misjudged as negative.

[0005] To solve the above technical problem, an immunodetection test strip for avoiding the HOOK effect provided by the utility model includes a bottom plate; a sample pad, a conjugate pad, an NC membrane, and a water absorption pad are sequentially arranged on the bottom plate, and at least two test lines and at least one quality control line are arranged on the NC membrane, and the test line, the quality control line are sequentially arranged on the NC membrane along the chromatography direction of the test strip.

[0006] A technical solution provided by this application further has the following technical features:

[0007] Preferably, the test line includes a T1 line and a T2 line, and the T1 line, the T2 line, and the quality control line are sequentially arranged on the NC membrane along the chromatography direction of the test strip. The T1 line is coated with an antibody specific to the antigen to be detected, and the T2 line is coated with the antigen to be detected.

[0008] Preferably, the quality control line includes a C line. Along the chromatographic direction of the test strip, a T1 line, a T2 line, and a C line are sequentially provided on the NC membrane. The C line is coated with goat anti-mouse secondary antibody.

[0009] Preferably, the bottom plate is made of PVC material.

[0010] Preferably, the conjugate pad is a gold label pad or a fluorescent microsphere pad.

[0011] Advantages of the present utility model:

[0012] The use of the gold label microsphere pad improves the sensitivity and specificity of the detection. The high electron density of the gold particles also facilitates electrochemical detection. Designing two T lines can effectively avoid misjudgment caused by excessive antigen to be detected, and improve the accuracy of the detection. The design of the test strip allows for rapid detection, and the result can be obtained in a short time, which is suitable for on-site rapid screening. The whole detection process is simple, and the user only needs to add the sample without complex operations. The C line serves as an internal control to ensure the reliability of each test and facilitate the user to judge whether the test is effective. Fluorescent labeling provides another detection method, which can be observed under an ultraviolet lamp, increasing the flexibility of the detection. The NC membrane serves as a chromatographic medium, which helps to separate and enrich the antigen to be detected and improve the accuracy of the detection. The components of the test strip are fixed stably, ensuring the repeatability and consistency of the detection results. The design of the test strip makes it easy to store in a dry state, facilitating transportation and distribution. Compared with traditional laboratory detection methods, the test strip detection is cost-effective and suitable for large-scale screening. Description of the Drawings

[0013] Figure 1 is a three-dimensional view of an immunodetection test strip that avoids the HOOK effect.

[0014] As shown in the figure:

[0015] 1. Sample pad; 2. Conjugate pad; 3. NC membrane; 4. T1 line; 5. T2 line; 6. C line; 7. Absorbent pad; 8. Bottom plate; 9. Detection line. Detailed Embodiments

[0016] The following will further illustrate the detailed embodiments of the present utility model with reference to the drawings. The same components are denoted by the same reference numerals.

[0017] It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the terms "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component.

[0018] In order to make the content of the present utility model more clearly understood, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings in the embodiments of the present utility model.

[0019] Combined with the attached Figure 1 As shown, an immunoassay test strip for avoiding the HOOK effect includes a base plate 8; a sample pad 1, a conjugate pad 2, an NC membrane 3, and an absorbent pad 7 are arranged in sequence on the base plate 8. At least two test lines 9 and at least one control line are provided on the NC membrane 3. Along the chromatography direction of the test strip, the test line 9 and the control line are arranged on the NC membrane 3 in sequence.

[0020] The sample pad 1 is the starting point of the test strip and is used to receive the sample containing the antigen to be detected. It is usually made of a highly water-absorbent material and can quickly absorb and disperse the sample. Cotton materials or synthetic fibers with good water absorption are used. It has the advantages of quickly absorbing the sample and ensuring the uniform advancement of the sample along the test strip.

[0021] The conjugate pad 2 is a gold-labeled pad or a fluorescent microsphere pad.

[0022] The gold-labeled pad and the fluorescent microsphere pad contain gold-labeled antibodies pre-fixed on the microspheres and are used to bind to the antigens in the sample. The gold particles increase the visibility of the label, and the microspheres increase the surface area and improve the reaction efficiency. The high electron density of the gold particles can also be used for electrochemical detection.

[0023] The NC membrane 3 serves as a chromatography medium and allows the liquid and molecules in the sample to move along the NC membrane 3. It has a screening effect on the molecular size and helps to separate and enrich the antigen to be detected. It is usually made of nitrocellulose, provides a chromatography effect, and helps to visualize the antigen-antibody complex.

[0024] The absorbent pad 7 is located at the end of the test strip and is used to absorb the excess sample and reagent to ensure the progress of the chromatography process. It is usually made of a highly water-absorbent material. High water-absorbent polymers or fiber materials are used to prevent the sample from overflowing and ensure the clarity of the test area.

[0025] The test line 9 includes a T1 line 4 and a T2 line 5. Along the chromatography direction of the test strip, the T1 line 4, the T2 line 5, and the control line are arranged on the NC membrane 3 in sequence. The T1 line 4 is coated with an antibody specific to the antigen to be detected, and the T2 line 5 is coated with the antigen to be detected.

[0026] The control line includes a C line 6. Along the chromatography direction of the test strip, the T1 line 4, the T2 line 5, and the C line 6 are arranged on the NC membrane 3 in sequence. The C line 6 is coated with a goat anti-mouse secondary antibody.

[0027] The T1 line 4 is coated with an antibody specific to the antigen to be detected and is used to capture the antigen bound to the gold-labeled antibody. When an appropriate amount of antigen is present, a red band will appear on the T1 line 4. Fixing the specific antibody on the test strip helps to detect the presence of the antigen and avoid the HOOK effect.

[0028] The 5th T line 5 is coated with the antigen to be detected itself, which is used to detect the binding of specific antibodies and antigens. When an appropriate amount of antigen is present, a red band will also appear on the T2 line 5. Fixing the antigen on the test strip provides another confirmation point for the detection.

[0029] The C line 6 is coated with goat anti-mouse secondary antibody, which serves as a control line to verify the effectiveness of the test process. Regardless of the amount of the antigen to be detected, as long as the test is valid, the C line 6 will show a red band. Fixing the secondary antibody on the test strip serves as an internal control to ensure the reliability of each test.

[0030] Under the action of chromatography, the sample moves along the test strip, binds to the gold-labeled antibody on the gold-labeled pad, and then passes through the T1 line 4, the T2 line 5, and the C line 6. The presence or absence and the concentration level of the antigen to be detected are judged based on the appearance or non-appearance of the red bands and their positions. Designing two T lines can effectively avoid the HOOK effect and improve the accuracy of the detection. If fluorescently labeled microspheres are used, the fluorescence signal can also be observed by irradiating with an ultraviolet lamp to achieve a more sensitive detection.

[0031] The bottom plate 8 is made of PVC material.

[0032] The working process of the present utility model:

[0033] Add the sample containing the antigen to be detected to the sample pad 1, and the sample pad 1 quickly absorbs and disperses the sample. The sample moves along the chromatography direction to the gold-labeled pad and binds to the gold-labeled antibody on the pad. The combined complex continues to move along the NC membrane 3 and passes through the T1 line 4, the T2 line 5, and the C line 6. The following situations will occur:

[0034] a. If the sample does not contain the antigen to be detected, no red band will appear on the T1 line 4, while red bands will appear on the T2 line 5 and the C line 6. Moreover, within a certain concentration range, as the antigen concentration increases, the color of the T1 line becomes darker and the color of the T2 line becomes lighter.

[0035] b. If the antigen to be detected in the sample is appropriate, red bands will appear on both the T1 line 4, the T2 line 5, and the C line 6.

[0036] c. If the antigen to be detected in the sample is excessive and exceeds the HOOK effect concentration, no red bands will appear on the T1 line 4 and the T2 line 5, and only the C line 6 will show a red band.

[0037] d. The C line 6 serves as a control line. Regardless of the amount of the antigen, as long as the test is valid, the C line 6 will show a red band.

[0038] The excess sample and reagent are absorbed by the water-absorbing pad 7, and the chromatography process ends.

[0039] Among them, if fluorescently labeled microspheres are used, corresponding fluorescent signals will appear on the T1 line 4, T2 line 5, and C line 6 under ultraviolet lamp irradiation.

[0040] The utility model has the following advantages:

[0041] The use of the gold label pad improves the sensitivity and specificity of the detection. The high electron density of the gold particles also facilitates electrochemical detection. Designing two T lines can effectively avoid misjudgment caused by excessive antigen to be detected, and improve the accuracy of the detection. The design of the test strip allows for rapid detection, and the results can be obtained in a short time, which is suitable for on-site rapid screening. The whole detection process is simple. The user only needs to add the sample without complex operations. The C line 6 serves as an internal control to ensure the reliability of each test and facilitate the user to judge whether the test is effective. Fluorescent labeling provides another detection method that can be observed under an ultraviolet lamp, increasing the flexibility of the detection. The NC membrane 3 serves as a chromatographic medium, which helps to separate and enrich the antigen to be detected and improve the accuracy of the detection. Each component of the test strip is fixed stably, ensuring the repeatability and consistency of the detection results. The design of the test strip makes it easy to store dry, facilitating transportation and distribution. Compared with traditional laboratory detection methods, test strip detection is cost-effective and suitable for large-scale screening.

[0042] The standard parts used in the utility model can all be purchased from the market. The special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, and welding that are mature in the prior art. The machines, parts, and equipment all adopt conventional models in the prior art. In addition, the circuit connection adopts the conventional connection method in the prior art, which will not be elaborated here. The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0043] The above describes the utility model and its implementation manners. Such description is not restrictive. What is shown in the drawings is only one of the implementation manners of the utility model, and the actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and without departing from the creative purpose of the utility model, they design similar structural manners and embodiments to this technical solution without creative efforts, which shall fall within the protection scope of the utility model.

Claims

1. An immunochromatographic test strip for avoiding the HOOK effect, comprising a bottom plate; characterized in that: The sample pad, conjugate pad, NC membrane, and absorbent pad are sequentially arranged on the bottom plate. At least two test lines and at least one control line are provided on the NC membrane. The test lines and the control line are sequentially arranged on the NC membrane along the chromatographic direction of the test strip.

2. The immunochromatographic test strip for avoiding the HOOK effect according to claim 1, characterized in that: The test lines include T1 line and T2 line. The T1 line, T2 line, and control line are sequentially arranged on the NC membrane along the chromatographic direction of the test strip. The T1 line is coated with an antibody specific to the antigen to be detected, and the T2 line is coated with the antigen to be detected.

3. An immunochromatographic test strip for avoiding HOOK effect according to claim 1 or 2, characterized in that: The control line is the C line. The T1 line, T2 line, and C line are sequentially arranged on the NC membrane along the chromatographic direction of the test strip. The C line is coated with goat anti-mouse secondary antibody.

4. The immunodetection test strip for avoiding the HOOK effect according to claim 1, wherein: The bottom plate is made of PVC material.

5. The immunochromatographic test strip for avoiding HOOK effect according to claim 1, characterized in that: The conjugate pad is a gold-labeled pad or a fluorescent microsphere pad.

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