Immunochromatography detection device based on time control and test method thereof

Abstract

The invention discloses an immunochromatography detection device based on time control and a test method thereof.According to the immunochromatography detection device, an electrode layer is added in a test strip, and the starting moment when a detected sample completely covers a reaction area is obtained by detecting an electric signal generated after the detected sample flows through an electrode in a specific area; therefore, the aim of accurately setting the timing starting point is fulfilled; meanwhile, timing can be carried out according to a timing program in a testing instrument, or an electrical timing device of a non-testing instrument is adopted for timing, sample adding and timing are carried out outside the testing instrument, and after timing is up, a measurement target in a tested sample is detected, so that the detection process is simple and convenient. According to the immunochromatography detection device, measurement errors caused by manual timing in a traditional timing mode are overcome, the labor cost is reduced, and the detection accuracy is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of immunochromatographic detection, and in particular relates to an immunochromatographic test strip based on time control and a testing method thereof. Background Art

[0002] Immunochromatographic test strips are a simple method that uses immunochromatography to detect the target substance through antigen-antibody reaction and color development, fluorescence emission, or reflection by the labeled substance. They are generally divided into colloidal gold and immunofluorescence chromatography methods. Generally, the colloidal gold method is used for qualitative detection, while the immunofluorescence chromatography method is used for quantitative detection. Immunofluorescence testing requires higher precision than the colloidal gold method.

[0003] Immunochromatography (using the sandwich method as an example) involves applying the sample to a sample pad. The antigen to be tested binds to an antibody labeled with fluorescein or fluorescent microspheres on the conjugate pad. The antigen bound to the labeled antibody at the T-line (test line) on the nitrocellulose membrane is captured by the antibody immobilized there. The downstream C-line (control line) uses the same principle and method to capture the labeled control substance. Under the excitation of light of a specific wavelength, the fluorescein or silver microspheres emits fluorescence at a different wavelength than the incident wavelength, which is detected by the instrument. The ratio of the T-line to C-line light intensities, combined with a defined regression curve, provides the precise concentration of the test substance.

[0004] However, lateral flow test strip testing involves a sample solution gradually flowing through the C-line and T-line. The length of time the C-line and T-line are in contact with the sample during this process will affect the final result. Generally, operators will manually time the test and perform the test within a certain period of time. However, because the progress of the immunochromatographic reaction is closely related to time, and the immunofluorescence chromatography test strip is under non-fluorescent conditions, it is difficult to visually determine whether the timing conditions have been triggered, and there is also a large degree of uncertainty. Therefore, manually judging the reaction time point will cause measurement errors and even erroneous test information.

[0005] To avoid this, CN205608002U uses a constant temperature timing device, but this approach places high demands on the instrument and cannot achieve high-throughput simultaneous testing. US5719034 incorporates an optical chemical reaction testing system into the test strip. The test time is inferred by the color change caused by the reaction of a set concentration of reactants in this optical system after being covered with liquid. However, this design's timing is affected by various factors of the photochemical reaction, making it impossible to achieve precise timing. Summary of the Invention

[0006] The present invention aims to provide a time-controlled immunochromatographic detection device and its testing method. By integrating a timing device into the test strip function and allowing an instrument to recognize the time prompts generated by the timing device changes, the timing test device for immunofluorescence test strips becomes a convenient and feasible method.

[0007] In a first aspect, the present invention provides a time-controlled immunochromatographic test strip comprising an adsorption layer and, stacked sequentially from bottom to top, a substrate layer, an electrode layer, and a nitrocellulose layer; the electrode layer comprises at least a first electrode and a second electrode. The adsorption layer comprises a sample loading pad and a conjugation pad. The sample loading pad, conjugation pad, and nitrocellulose layer are sequentially connected. The nitrocellulose layer is provided with a quality control line and a test line.

[0008] The first electrode is aligned with the quality control line on the nitrocellulose layer. The second electrode is aligned with the quality control line on the nitrocellulose layer, or any position between the quality control line and the connection between the nitrocellulose layer and the conjugate pad. The first electrode and the second electrode are spaced apart and are initially non-conductive.

[0009] Preferably, the electrode layer further comprises a wire; the first electrode and the second electrode are led out through independent wires, and an insulating structure is provided between the wire and the nitrocellulose layer.

[0010] Preferably, the insulating structure adopts an insulating layer located between the electrode layer and the nitrocellulose layer, and the insulating layer is provided with windows corresponding to the first electrode and the second electrode.

[0011] Preferably, the insulating layer is provided with only one window, the window is aligned with the quality control line, and the first electrode and the second electrode are only within the window.

[0012] Preferably, the insulating layer is provided with two windows, namely a first window and a second window, and the first window and the second window are aligned with the first electrode and the second electrode respectively.

[0013] Preferably, the quality control line, the first window and the first electrode are aligned; the test line, the second window and the second electrode are aligned.

[0014] Preferably, the sample loading pad is made of fiberglass; the conjugate pad overlaps the end of the nitrocellulose layer. The other end of the conjugate pad overlaps the end of the sample loading pad. The conjugate pad is located on the side of the test line away from the quality control line; the end of the sample loading pad facing away from the conjugate pad is used to place the sample to be tested; and the conjugate pad is provided with fluorescent microspheres or fluorescein-conjugated antigens or antibodies.

[0015] Preferably, the adsorption layer further comprises a water-absorbing membrane. One end of the water-absorbing membrane overlaps the end of the nitrocellulose layer facing away from the conjugate pad. The other end of the water-absorbing membrane is bonded to the insulating layer via an adhesive layer or directly to the substrate layer via the insulating layer. The water-absorbing membrane is used to absorb excess liquid and guide the liquid toward the quality control line.

[0016] Preferably, the substrate layer is made of polyvinyl chloride or polyethylene terephthalate.

[0017] Preferably, the electrode layer further includes a wire; the first electrode and the second electrode are led out through two independent wires respectively.

[0018] Preferably, the immunochromatographic test strip further comprises a lateral flow cartridge. The substrate layer, electrode layer, nitrocellulose layer, and adsorption layer are disposed within the inner cavity of the lateral flow cartridge. The lateral flow cartridge is provided with a sample loading opening aligned with the sample loading pad, and an optical detection window is formed between the conjugate pad and the absorbent membrane. The lateral flow cartridge exposes the end of the electrode layer facing away from the sample loading pad. The ends of the two wires extend to the exterior of the lateral flow cartridge, forming a conductive interface, allowing an external instrument to detect electrical continuity between the first electrode and the second electrode.

[0019] Preferably, the electrode layer is fixed on the substrate layer by screen printing.

[0020] Preferably, the electrode layer is modified on the substrate layer by sputtering using metal or semiconductor.

[0021] Preferably, the insulating layer is formed by curing insulating ink on the electrode layer in a UV curing or heat curing manner.

[0022] Preferably, the nitrocellulose layer and the adsorption layer are fixed on the base material layer or the insulating layer through an adhesive layer, and the adhesive layer is provided with windows corresponding to the first window and the second window.

[0023] Preferably, a non-conductive adhesive layer is directly used as the insulating layer. The nitrocellulose layer and the adsorption layer are fixed on the substrate layer via the adhesive layer.

[0024] In a second aspect, the present invention provides a time-controlled immunochromatographic detection device comprising a detection instrument with an electrochemical timing function and the aforementioned test strip. The detection instrument is configured to detect the reflected fluorescence intensity of a test line and a control line. The detection instrument is provided with electrode interfaces corresponding to the first electrode and the second electrode.

[0025] In a third aspect, the present invention provides a testing method for an immunochromatographic detection device based on time control, the testing method comprising the following steps: Step 1: Insert the test strip into the test instrument, ensuring that the first and second electrodes are electrically connected to the two electrode interfaces of the test instrument through the wires. The test instrument continuously detects whether the first and second electrodes are electrically connected. Add the sample to be tested to the sample pad.

[0026] In step 2, the sample passes through the conjugate pad, forming an antigen-antibody complex. The combined antigen-antibody complex and the sample reach the nitrocellulose layer. When the sample reaches the control line, both the first and second electrodes are wetted and connected. The instrument uses the moment of conductive contact between the first and second electrodes as the start time.

[0027] Step 3: After waiting for a preset time, the detection instrument detects the reflected fluorescence intensity of the test line and the quality control line, and obtains the content of the measured target substance in the tested sample through the ratio of the reflected fluorescence intensities.

[0028] Preferably, the process of the detection instrument continuously detecting whether the first electrode and the second electrode are conductive is as follows: the detection instrument continuously applies a constant potential difference or AC signal between the first electrode and the second electrode, and obtains a timing start signal of the first electrode and the second electrode based on the generated current and impedance changes.

[0029] Preferably, the first electrode and the second electrode are covered with an electroactive material so that when they are turned on, a stronger signal change can be generated to support the start of timing.

[0030] Preferably, when applying a potential difference, the potential difference applied by the detection instrument is in the range of 5mV to 1000mV; when applying an AC signal, the AC signal is one of a sine wave, a square wave and a triangle wave.

[0031] In a fourth aspect, the present invention provides an external electrochemical timing instrument having an electrode interface that mates with the electrical interface formed by the wires on the aforementioned immunochromatographic test strip. During operation, the electrodes of the test strip are first docked with the electrode interface of the external electrochemical timing instrument. When the first and second electrodes are electrically connected, timing begins. When timing is complete, the immunochromatographic test strip reaction is complete. After the reaction is complete, the test strip can be transferred to a fluorescence detection instrument for optical detection.

[0032] In a fifth aspect, the present invention provides an immunochromatographic detection device based on time control, which includes the above-mentioned immunochromatographic test strip, a fluorescence detection instrument and an external electrochemical timing instrument; the external electrochemical timing instrument is provided with an electrode interface; the electrode interface matches the electrical interface formed by the wire on the immunochromatographic test strip. During operation, the test strip is inserted, and the electrodes on the test strip are docked with the electrode interface inside the external electrochemical timing instrument; when the first electrode is connected to the second electrode, timing begins; after the timing is completed, the reaction of the immunochromatographic test strip is completed. The fluorescence detection instrument is used to perform fluorescence detection on the immunochromatographic test strip after the reaction is completed.

[0033] The present invention has the following beneficial effects: 1. The present invention adds an electrode layer to the test strip. By detecting the change in the electrical signal after the test sample flows through the electrode pair, the time when the test sample completely covers the reaction area of ​​the lateral flow test strip is determined, thereby achieving the purpose of accurately setting the timing starting point. At the same time, timing is performed according to the timing program in the test instrument, or using an electrical timing device other than the measuring instrument. Sample addition and timing are performed outside the measuring instrument. After the timing is reached, the measurement target in the test sample is detected, and the detection process is simple and convenient.

[0034] 2. The precise setting of the timing starting point of the present invention overcomes the measurement error caused by manual timing in traditional timing methods, reduces labor costs, and improves detection accuracy. At the same time, the present invention has a simple structure, low requirements for instruments, and is not affected by environmental interference.

[0035] 3. The present invention can split the timing and detection functions so that the detection device can synchronously time multiple test strips and then detect the test strips after the timing ends, thereby avoiding the test strips waiting on the fluorescence detection instrument; by matching multiple external electrochemical timing instruments with one fluorescence detection instrument, the test throughput can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a top view of each layer of the test strip in Example 1 of the present invention.

[0037] Figure 2 This is a side view of the test strip in Example 1 of the present invention.

[0038] Figure 3 This is a top view of each layer of the test strip in Example 2 of the present invention.

[0039] Figure numerals: 1, substrate layer; 2, electrode layer; 3, insulating layer; 4, nitrocellulose layer; 5, adsorption layer; 201, first electrode; 202, second electrode; 203, first wire; 204, second wire; 301, first window; 302, second window; 401, quality control line; 402, test line; 501, sample pad; 502, binding pad; 503, water-absorbing membrane. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the accompanying drawings.

[0041] Example 1 like Figure 1 and 2 As shown, a time-controlled immunochromatographic detection device includes a test strip and a detection instrument with an electrochemical timing function. The test strip comprises a lateral flow cartridge, an adsorption layer 5, and, from bottom to top, a substrate layer 1, an electrode layer 2, an insulating layer 3, and a nitrocellulose layer 4. The substrate layer 1 is made of PVC (polyvinyl chloride) or PET (polyethylene terephthalate). The electrode layer 2 includes a first electrode 201, a second electrode 202, a first wire 203, and a second wire 204. The first and second electrodes 201, 202 are connected via independent first and second wires 203, 204, respectively. The electrode layer is screen-printed onto the substrate layer using a printable ink selected from carbon ink, metallic ink, and semiconductor ink. The first and second electrodes 201, 202 are connected to the detection instrument via the first and second wires 203, 204, respectively, to create a potential difference, which transmits electrical signals to the instrument. The insulating layer 3 is formed by curing insulating ink on the electrode layer 2 by UV curing (ultraviolet curing) or thermal curing, and is used to prevent conduction between the nitrocellulose layer 4 and the electrode layer 2; a first window 301 and a second window 302 are provided on the insulating layer 3.

[0042] The nitrocellulose layer 4 is bonded to the insulating layer 3 via an adhesive layer. Parallel control lines 401 and test lines 402 are provided on the nitrocellulose layer 4. The control lines 401, the first window 301, and the first electrode 201 are aligned, and the first electrode 201 and the control lines 401 are connected through the first window 301. The test lines 402, the second window 302, and the second electrode 202 are aligned, and the second electrode 202 and the test lines 402 are connected through the second window 302.

[0043] The adsorption layer 5 includes a sample loading pad 501, a conjugation pad 502, and a water-absorbing membrane 503; the sample loading pad 501 is made of glass fiber, and the sample loading pad 501, the conjugation pad 502, and the nitrocellulose layer 4 are connected in sequence. The conjugation pad 502 overlaps with the end of the nitrocellulose layer 4. The other end of the conjugation pad 502 overlaps with the end of the sample loading pad 501. The conjugation pad 502 is located on the side of the test line 402 away from the quality control line 401; the end of the sample loading pad 501 away from the conjugation pad 502 is used to place the sample to be tested; the conjugation pad 502 is provided with fluorescent microspheres or fluorescein-bound antigens or antibodies; one end of the water-absorbing membrane 503 overlaps with the end of the nitrocellulose layer 4 away from the conjugation pad 502. The other end of the water-absorbing membrane 503 is bonded to the insulating layer 3 by an adhesive layer. The water-absorbing membrane 503 is used to absorb excess liquid and guide the liquid to move toward the quality control line 401 to ensure uniform distribution of the test sample.

[0044] In some embodiments, the electrode layer is modified on the substrate layer by sputtering using metal or semiconductor.

[0045] In some embodiments, the first electrode 201, the second electrode 202, the first wire 203 and the second wire 204 are all made of one or more of carbon, graphite, silver, silver / silver chloride, silver / silver bromide, silver / silver iodide, copper, gold, titanium, nickel, gallium nitride and titanium nitride, preferably carbon or silver.

[0046] In some embodiments, the insulating layer 3 and the adhesive layer are combined into one layer, and the non-conductive adhesive layer is used as the insulating layer 3 .

[0047] The substrate layer 1, electrode layer 2, insulating layer 3, nitrocellulose layer 4, and adsorption layer 5 are arranged in the inner cavity of the lateral flow cartridge. The lateral flow cartridge is provided with a sample loading opening aligned with the sample loading pad 501, and an optical detection window is formed between the sample loading pad 501 and the water-absorbing membrane 503. The lateral flow cartridge completely covers the nitrocellulose layer 4 and the adsorption layer 5, and exposes the end of the electrode layer 2 facing away from the sample loading pad 501. The ends of the first wire 203 and the second wire 204 extend to the outside of the lateral flow cartridge and form a conductive interface; the detection instrument is used to detect the reflected fluorescence intensity of the quality control line 401 and the test line 402. The detection instrument is provided with a connector, and the connector is provided with two electrode interfaces corresponding to the first electrode 201 and the second electrode 202, respectively.

[0048] The working principle of the time-controlled immunochromatographic detection device is as follows: Step 1: Insert the test strip into the test instrument's insertion port, with the portion of the test strip exposed near the lateral flow cartridge inserted into the test instrument's connector, so that the first electrode 201 and the second electrode 202 are electrically connected to the connector's two electrode interfaces. The instrument continuously applies a constant potential difference or AC signal between the first electrode 201 and the second electrode 202 through the connector. When applying a potential difference, the potential difference applied by the test instrument ranges from 5mV to 1000mV. When applying an AC signal, the AC signal is one of a sine wave, a square wave, and a triangular wave. The test instrument detects whether the first electrode 201 and the second electrode 202 are electrically connected based on changes in the current or impedance generated between the first electrode 201 and the second electrode 202. After the test instrument prompts you to add the sample to be tested, the sample to be tested is added to the sample pad 501 through the sample loading port provided on the lateral flow cartridge.

[0049] Step 2: The sample to be tested, added to the sample pad 501, flows toward the conjugate pad 502. The antigen or antibody bound to the fluorescent microspheres or fluorescein on the conjugate pad 502 binds to the sample to be tested, obtaining an antigen-antibody complex. The bound antigen-antibody complex flows with the sample solution to the nitrocellulose layer 4. The test line 402 on the nitrocellulose layer 4 captures the bound complex through the corresponding antigen or antibody, and infiltrates the second electrode 202 through the second window 302. The sample to be tested flowing through the test line 402 flows toward the quality control line 401. When flowing through the quality control line 401, the labeled quality control line substance is captured by the corresponding antibody at the quality control line 401, and the solution infiltrates the first electrode 201 through the first window 301. The detection instrument uses the moment when the current generated by the first electrode 201 and the second electrode 202 is greater than the preset current as the timing start moment.

[0050] Step 3: After waiting for a preset time, the detection instrument detects the reflected fluorescence intensity of the quality control line 401 and the test line 402, and obtains the content of the measured target substance in the sample through the ratio of the reflected fluorescence intensity according to the measured regression equation.

[0051] In some embodiments, the first electrode 201 and the second electrode 202 are covered with an electroactive substance so that a stronger signal can be generated when the conduction is turned on to support the start of timing. The electroactive substance covered on the first electrode 201 and the second electrode 202 is one or more of potassium ferrocyanide, potassium ferrocyanide, trichlorohexammineruthenium, ferrocene, methylene blue, NAD, FAD, PQQ, FMN, ABTS, tetrathiafulvalene and menadione, preferably potassium ferrocyanide and potassium ferrocyanide.

[0052] Example 2 like Figure 3As shown, an immunochromatographic detection device based on time control is different from Example 1 in that: in this embodiment, the second electrode 202 is located near the quality control line 401 (specifically, the side of the quality control line 401 close to the test line 402); in this embodiment, only the first window 301 is provided; the first electrode 201 and the second electrode 202 are both within the range of the first window 301.

[0053] Example 3 An external electrochemical timing instrument is provided with an electrode interface matching the electrical interface formed by the first wire 203 and the second wire 204, and is used for simultaneously adding samples and timing multiple test strips.

[0054] During operation, the test strip is first inserted into the electrode interface of an external electrochemical timing instrument. The timing begins after the first electrode 201 and the second electrode 202 are electrically connected. After the preset reaction time, the test strip is removed from the external electrochemical timing instrument and inserted into a fluorescence detection instrument. The fluorescence detection instrument then measures the reflected fluorescence intensity of the control line 401 and the test line 402.

[0055] The external electrochemical timing instrument provided in this embodiment enables the test strip to be loaded and waited for outside the fluorescence detection instrument; it avoids the test strip waiting on the fluorescence detection instrument; and by matching multiple external electrochemical timing instruments with one fluorescence detection instrument, the test throughput can be effectively improved.

[0056] Example 4 A time-controlled immunochromatographic detection device comprises a test strip, a lateral flow cartridge, a fluorescence detection instrument, and a plurality of external electrochemical timing instruments; the test strip and the lateral flow cartridge are the same as those in Example 1; and the external electrochemical timing instruments are the same as those in Example 3.

Claims

1. An immunochromatographic test strip based on time control, characterized in that: The invention comprises an adsorption layer (5) and a substrate layer (1), an electrode layer (2), and a nitrocellulose layer (4) stacked in sequence from bottom to top; the electrode layer comprises a first electrode (201) and a second electrode (202); the adsorption layer (5) comprises a sample loading pad (501) and a binding pad (502); the sample loading pad (501), the binding pad (502), and the nitrocellulose layer (4) are connected in sequence; and a quality control line (401) and a test line (402) are provided on the nitrocellulose layer (4); The first electrode (201) is aligned with the quality control line (401) on the nitrocellulose layer (4); the second electrode (202) is aligned with the quality control line (401) on the nitrocellulose layer (4), or any position between the quality control line (401) and the connection between the nitrocellulose layer (4) and the binding pad (502).

2. The time-controlled immunochromatographic test strip according to claim 1, characterized in that: The electrode layer (2) further comprises a wire; the first electrode (201) and the second electrode (202) are respectively led out through independent wires; and an insulating structure is provided between the wire and the nitrocellulose layer (4).

3. The time-controlled immunochromatographic test strip according to claim 2, characterized in that: The device also comprises a lateral chromatography cartridge; the substrate layer (1), the electrode layer (2), the nitrocellulose layer (4) and the adsorption layer (5) are arranged in the inner cavity of the lateral chromatography cartridge; the lateral chromatography cartridge is provided with a sample loading opening aligned with the sample loading pad (501); the lateral chromatography cartridge is completely covered with the insulating layer (3) and the end of the electrode layer (2) facing away from the sample loading pad (501) is exposed; the ends of the two wires are extended to the outside of the lateral chromatography cartridge to form a conductive interface.

4. The time-controlled immunochromatographic test strip according to claim 2, characterized in that: The insulating structure adopts an insulating layer (3) located between the electrode layer (2) and the nitrocellulose layer (4), and windows corresponding to the first electrode (201) and the second electrode (202) are provided on the insulating layer (3).

5. The time-controlled immunochromatographic test strip according to claim 4, characterized in that: The electrode layer (2) is fixed on the substrate layer by screen printing or modified on the substrate layer by sputtering using metal or semiconductor; the insulating layer (3) is formed by curing insulating ink on the electrode layer (2) by ultraviolet curing or thermal curing.

6. An immunochromatographic detection device based on time control, characterized in that: The invention comprises a detection instrument for detecting the immunochromatographic test strip as claimed in claim 1; the detection instrument is used for timing and detecting the reflected fluorescence intensity of the quality control line (401) and the test line (402); the detection instrument is provided with two electrode interfaces respectively corresponding to the first electrode (201) and the second electrode (202) in the immunochromatographic test strip.

7. A testing method for an immunochromatographic detection device based on time control, characterized in that: Using the time-controlled immunochromatographic detection device as described in claim 6; The test method includes the following steps: Step 1: insert the immunochromatographic test strip into the detection instrument so that the first electrode (201), the second electrode (202) and the two electrode interfaces of the detection instrument are respectively connected; the detection instrument continuously detects whether the first electrode (201) and the second electrode (202) are connected; and the sample to be tested is added to the sample pad (501); Step 2, the sample to be tested passes through the binding pad (502) to form an antigen-antibody complex; the bound antigen-antibody complex arrives on the nitrocellulose layer (4) along with the sample to be tested; when the sample to be tested reaches the quality control line (401), the first electrode (201) and the second electrode (202) are both wetted and turned on, and the detection instrument uses the moment when the first electrode (201) and the second electrode (202) are turned on as the timing start moment; Step 3: After waiting for a preset time, the detection instrument detects the reflected fluorescence intensity of the quality control line (401) and the test line (402), and obtains the content of the measured target substance in the measured sample through the ratio of the reflected fluorescence intensity.

8. The testing method of the immunochromatographic detection device based on time control according to claim 7, characterized in that: The process of the detection instrument continuously detecting whether the first electrode (201) and the second electrode (202) are conductive is as follows: the detection instrument continuously applies a constant potential difference or an AC signal between the first electrode (201) and the second electrode (202), and obtains a timing start signal based on the current change and impedance change generated between the first electrode (201) and the second electrode (202).

9. An external electrochemical timing instrument, characterized in that: An electrode interface is provided; the electrode interface matches the electrical interface formed by the wire on the immunochromatographic test strip as claimed in claim 2; during operation, the electrode of the test strip is first connected to the electrode interface of an external electrochemical timing instrument; when the first electrode (201) and the second electrode (202) are turned on, timing starts; after the timing is completed, the reaction of the immunochromatographic test strip is completed.

10. An immunochromatographic detection device based on time control, characterized in that: It comprises a fluorescence detection instrument and an external electrochemical timing instrument; the external electrochemical timing instrument is provided with an electrode interface; the electrode interface is used to connect with the electrical interface formed by the wire on the immunochromatographic test strip as claimed in claim 2; during operation, the electrode of the test strip is first connected to the electrode interface of the external electrochemical timing instrument; when the first electrode (201) and the second electrode (202) are turned on, timing starts; after the timing is completed, the reaction of the immunochromatographic test strip is completed; the fluorescence detection instrument is used to perform fluorescence detection on the immunochromatographic test strip after the reaction is completed.

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