A quality control product for cervical liquid-based cytology and its preparation method

Abstract

The present invention relates to the technical field of cytopathology detection, and in particular to a quality control product for cervical liquid-based cytology projects and a preparation method thereof; the product comprises quality control cells and a cervical liquid-based cytology preservation fluid, wherein the quality control cells are extracted from cervical liquid-based cytology samples; the inventors prepare the quality control product by collecting samples remaining after routine clinical pathology laboratory testing, and perform dynamic observation and analysis to ultimately obtain the above-mentioned quality control product for cervical liquid-based cytology projects. The quality control product is prepared by classifying, breaking up, filtering, washing, fixing, shedding, removing residues, extracting and other steps of a plurality of cervical exfoliated liquid-based cytology samples from different individuals, without causing mutual influence or interference, and can be preserved for a long time, having the feasibility of being used as a quality control product, and having good stability, and can be used as a quality control product in routine quality control in clinical pathology laboratories.

Description

Technical Field

[0001] The present invention relates to the technical field of cytopathology detection, and in particular to a quality control product for cervical liquid-based cytology items and a preparation method thereof. Background Art

[0002] Quality control is a crucial measure for ensuring accurate and reliable laboratory test results, and in-house quality control products are an essential component of the quality control system. Appropriate quality control products can be used to monitor the stability of the laboratory's testing system, which includes testing instruments, reagents, reference materials, and other experimental conditions. This ensures accurate and reliable test results, thereby providing essential occupational health services.

[0003] Clinically, early diagnosis of cervical disease is often performed through cervical cytology, providing a foundation for evidence-based medicine. Many cervical cytology tests are performed using liquid-based cytology. While liquid-based cytology offers advantages such as high sensitivity and specificity, it also suffers from potential high background, cell dropout, intercellular contamination, and insufficient effective cell counts. Therefore, the reliability of these results can be effectively monitored using stable in-house quality control products.

[0004] At the same time, cervical liquid-based cytology projects generally require frequent replacement of reagents, instruments, and personnel during the testing process, and go through multiple links to complete the entire testing process. Therefore, cervical liquid-based cytology quality control products are a very convenient and effective tool for testing cervical diseases that can provide guaranteed results.

[0005] However, there are currently no commercialized quality control products for cervical liquid-based cytology testing on the market, and the suppliers of cervical liquid-based cytology testing consumables themselves are unable to provide matching quality control products. In order to meet the needs of in-house quality control, the alternative method currently used by clinical pathology laboratories is to randomly select 1 to 3 extra half-bottle samples from the previous day's testing, and use them as alternative quality control products for secondary testing the next day, thereby performing comparisons in units of two days as a compensatory measure for in-house quality control. Although this method seems to be able to replace the effect of quality control products, it has the following significant disadvantages:

[0006] The remaining sample volume of the alternative quality control product is too small, because it has been tested once the day before, consuming more than half of the sample volume. The remaining sample volume is only enough for 1 to 2 more tests and comparisons. Some brands even have insufficient remaining sample volume for one more test. As a result, if there is a difference in the comparison results between two days, there will be no more samples with the same characteristics to re-verify the effect evaluation after finding the cause of the problem and formulating improvement measures.

[0007] When using a randomly selected excess sample as a quality control, the quality of the specimen preparation may differ between the two tests, or the results may differ. This can be caused by improper operation during the first test, resulting in the second quality control test achieving better quality and results than the first. This means that the excess sample was already out of control when it was first used in clinical testing, but the lack of continuous comparisons prevented the problem from being discovered.

[0008] Because the remaining sample volume is too small, it is impossible to conduct comparisons between multiple people, multiple instruments, or multiple processes. This is one of the reasons why there are national inter-laboratory comparisons for histopathology projects in the field of pathology technology, but no inter-laboratory comparisons for cytopathology projects, because it is difficult to obtain large quantities of samples with the same or similar characteristics for packaging.

[0009] The causes and solutions to the above three shortcomings all require repeated testing with a large number of specimens of the same or similar characteristics. To obtain a large number of quality control substitute samples, some have attempted to collect and mix the remaining samples after multiple tests. However, it was found that when samples from different individuals were mixed together, a certain degree of cell aggregation and mucus-like material appeared, leading to significant cell overlap or shedding after slide preparation; sometimes, a jelly-like substance even appeared, making it impossible to use as a substitute quality control product for multiple consecutive days. Furthermore, the consumables used in cervical liquid-based cytology testing programs have limited or no fixation efficacy, and the preservation fluid cannot preserve the original characteristics of the samples for a long time. Summary of the Invention

[0010] The purpose of the present invention is to provide a quality control product for cervical liquid-based cytology that is readily available and used in routine quality control in clinical pathology laboratories. This product fills the gap in quality control products for cervical liquid-based cytology testing, addresses the three drawbacks of alternative quality control products described above, and facilitates operation while reducing costs. A method for preparing the quality control product for cervical liquid-based cytology is also provided.

[0011] The technical solutions adopted in the present invention are as follows:

[0012] A method for preparing a quality control product for cervical liquid-based cytology, comprising the following steps:

[0013] Quality control sample selection;

[0014] Quality control samples are broken up, filtered, and washed;

[0015] Quality control sample fixation;

[0016] Preparation of quality control cell suspension and assessment of effective cell number in suspension;

[0017] Quality control cell pooling: Pour the cell suspension directly into the same large bottle together with the fixative to obtain a mixed solution from multiple samples;

[0018] Remove cell debris sediment: Place the mixture on a shaker and start weak shaking to allow cell debris lighter than normal cervical epithelial cells to precipitate and float. During the shaking process, remove the upper half of the fixative in the bottle and add the same amount of new fixative. Continue shaking, aspirating, and replenishing three times. After the last aspiration of the upper half of the fixative, do not replenish it. After standing, obtain a visible cell layer at the bottom of the bottle.

[0019] Obtain quality control cells: aspirate all the fixative above the cell layer and discard it; aspirate the cell sediment in the upper third of the cell layer and discard it; aspirate the middle third of the cell layer as quality control cells and place them in a liquid-based cytology sample storage bottle as the stock solution for later use;

[0020] Preparation of quality control working solution: After shaking the entire bottle of stock solution, take a certain amount of stock solution for slide preparation and testing. Evaluate the number of cervical squamous epithelial cells after preparation. According to the number of cells on a single slide, add liquid-based cell preservation solution to the stock solution in a certain proportion and dilute it. Repeat the above steps until the number of cervical squamous epithelial cells on a single slide reaches between 8,000 and 12,000, and the cell overlap rate is less than 20%. This is defined as a qualified quality control product.

[0021] Furthermore, the quality control sample selection further includes the following steps:

[0022] 1) Preparation of cervical liquid-based cytology samples: Categorize multiple liquid-based cytology samples according to different age groups and prepare them for future use;

[0023] 2) Cervical liquid-based cytology sample testing: Take liquid-based cytology samples containing the same classification for testing, obtain the test results, and keep them for future use;

[0024] 3) Selection of quality control cell extraction samples: According to the same classification, multiple liquid-based cytology samples with the same test results are collected as quality control cell extraction samples for future use;

[0025] 4) Assembly of the quality control sample precipitation mold: Use a non-adhesive pathology slide as the negative film, and assemble the filter membrane net, fixed mold and negative film that come with the liquid-based cytology project product to form a new liquid-based cytology precipitation mold. The upper half of the mold is the sample loading layer, the lower half is the cleaning layer, and the filter membrane net is used as the boundary in the middle for future use.

[0026] Furthermore, in the quality control cell extraction sample selection step, the number of cervical squamous epithelial cells contained in the test results is greater than 8,000.

[0027] Furthermore, the breaking up, filtering and washing of the quality control samples specifically include the following steps:

[0028] 1) Pour the cleaning solution provided with the liquid-based cytology product into the cleaning layer of the mold, pour the sample to be extracted into the sample layer of the mold, place the mold in a centrifuge and centrifuge at high speed, then let it stand; aspirate the liquid in the sample layer of the mold, remove the mold filter membrane, and aspirate the upper third of the liquid in the lower half layer;

[0029] 2) Repeat washing: Add physiological saline to the mold until the liquid level reaches two-thirds of the mold. Use a pipette to blow the bottom of the mold to mix the physiological saline and cleaning solution. Then place the mold in a centrifuge at high speed and centrifuge it. Let it stand. Aspirate two-thirds of the liquid on the mold. Then add the same amount of physiological saline. After blowing, centrifuge it. Let it stand and aspirate two-thirds of the liquid on the mold. This will obtain relatively pure quality control cells and cell debris sediment for use.

[0030] Furthermore, the quality control sample fixation includes the following steps:

[0031] 1) Preparation of quality control sample fixative: dissolve paraformaldehyde, sodium dihydrogen phosphate, and disodium hydrogen phosphate in distilled water, mix thoroughly, and allow to stand for later use.

[0032] 2) Fixation of quality control samples: Add fixative to the mold until the liquid volume reaches two-thirds of the mold height, thus completing the fixation of quality control cells, precipitating cell proteins, inactivating cell zymogens, and cross-linking and fixing intracellular macromolecules, thereby blocking possible cross-adsorption or abnormal reactions between different individuals.

[0033] Furthermore, in the quality control sample selection step: a sample without blood, mucus, and impurities visible to the naked eye is selected, wherein the number of cervical squamous epithelial cells is greater than 8,000.

[0034] Furthermore, the preparation of the quality control cell suspension includes the following steps: repeatedly blowing the bottom of the mold with a pipette to make the cells attached to the glass slide due to centrifugation fall off the glass slide to form a cell suspension.

[0035] Furthermore, the evaluation of the effective cell number of the suspension includes the following steps: taking the cell suspension, dropping it on a clean pathology slide, covering it with a coverslip, observing it under a microscope, and counting the number of squamous epithelial cells contained therein, so as to achieve a cell number of ≥1 per μl of suspension to be qualified; otherwise, it is necessary to continue blowing the bottom of the mold to detach the attached cells.

[0036] Furthermore, the quality control product is refrigerated at 4°C to 8°C.

[0037] The quality control product of cervical liquid-based cytology project prepared by the above preparation method.

[0038] The beneficial effects of adopting the technical solution of the present invention are:

[0039] The inventors prepared quality control products by collecting samples of different cervical liquid-based cytology projects with qualified effective numbers of cervical exfoliated cells, classified in the same age group, and with the same test results, and conducted dynamic observation and analysis to finally obtain the above-mentioned cervical liquid-based cytology project quality control products. Multiple cervical exfoliated cytology samples from different individuals were prepared through classification, dispersion, filtration, washing, fixation, exfoliation, deslagging, extraction and other steps. They will not produce mutual influence and interference, and can be preserved for a long time. They are feasible as quality control products and have good stability. They can be used as quality control products in daily quality control of clinical pathology laboratories. DETAILED DESCRIPTION

[0040] The present invention is further illustrated by the following examples, but the invention is not limited to the scope of these examples. Experimental methods and conditions not specified in the following examples were performed according to conventional methods and conditions, or according to the product specifications. Unless otherwise specified, the reaction temperature is generally room temperature, which in this invention refers to 10-30°C.

[0041] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0042] Unless otherwise specified, the materials and reagents used in the following examples can be purchased from commercial sources.

[0043] The cervical liquid-based cytology preservation solution in the present invention adopts KS103-BC produced by Guangzhou Jinqirui Biotechnology Co., Ltd.

[0044] 1. Sample collection.

[0045] Through the pathology information system (LIS system), the cases reported in the past 7 to 14 days were searched, and 1,000 to 1,500 cases with no abnormal changes in the diagnosis results and the number of cervical squamous epithelial cells greater than 8,000 were selected, and the case list was exported.

[0046] The samples were found according to the list. By visually inspecting the sample characteristics, bloody samples, samples containing mucus, and samples containing visible impurities were removed. The remaining samples were the quality control cell extraction samples, which amounted to approximately 900 to 1,300.

[0047] The target samples are classified into four categories based on age groups: “≤30 years old”, “30-50 years old”, “51-60 years old”, and “60 years old ≥”.

[0048] Preparation of mold and fixative:

[0049] Assembly of the quality control sample precipitation mold: Disassemble the liquid-based cytology product mold, remove the filter membrane and fixed mold, and reassemble them using a non-adhesive pathology slide as the bottom film to form a new liquid-based cytology precipitation mold. The upper half of the mold is the sample loading layer, the lower half is the washing layer, and the filter membrane is used as the boundary in the middle, which is reserved for future use.

[0050] Prepare the fixative for quality control samples: Dissolve 400g of paraformaldehyde, 40g of sodium dihydrogen phosphate, and 65g of disodium hydrogen phosphate in 1000ml of distilled water, mix thoroughly, and let stand to obtain 1000ml of fixative. Prepare 2000-3000ml of fixative according to this recipe. Other preparations: Prepare several bottles of normal saline, cleaning solution, and preservation solution from the liquid-based cytology product kit.

[0051] 2. Extraction and preparation of quality control products:

[0052] Among the target samples classified by age group, 200 to 250 quality control cell extraction samples of the same age group were taken and the same number of molds were prepared;

[0053] Pour the cleaning liquid into the mold cleaning layer until the liquid level just touches the mold filter membrane;

[0054] Manually shake the quality control cell extraction sample up and down several times, open the bottle cap, and slowly pour it into the sample layer of the mold along the edge of the mold to about two-thirds of the height of the sample layer;

[0055] Place the molds into the centrifuge and balance them two by two. Set the centrifuge speed to 2500-3000 rpm and the centrifugal time to 5-6 minutes. Start the centrifuge and wait for it to stop completely. Let it stand for 5-6 minutes and then take out the molds.

[0056] Use a pipette to suck out the liquid in the sample layer of the mold, gently remove the mold filter membrane, and then gently suck out about one-third of the liquid above the cleaning layer along the surface of the cleaning layer;

[0057] Add physiological saline to the mold until the liquid level reaches two-thirds, and gently blow the bottom of the mold with a pipette to mix the physiological saline and cleaning solution. Then place the mold in a centrifuge, centrifuge at high speed, and let it stand. Aspirate about two-thirds of the liquid on the mold, then add an equal amount of physiological saline, blow it, centrifuge it, let it stand, and aspirate two-thirds of the liquid on the mold. This will obtain relatively pure quality control cells and cell debris sediment for use.

[0058] Aspirate about two-thirds of the liquid on the mold to obtain a relatively pure liquid containing quality control cells and cell debris sediment;

[0059] Add fixative solution to the mold, filling it to approximately two-thirds of the way. This fixates the quality control cells, precipitating cellular proteins, inactivating zymogens, and cross-linking and fixing intracellular macromolecules, thereby preventing any cross-adsorption or abnormal reactions between cells. Because the fixative solution is made with formaldehyde, which is harmful to the human respiratory tract and ocular mucosa, this step must be performed in a biosafety cabinet with the exhaust system activated.

[0060] Cell fixation is automatic, so there is no need to wait and proceed directly to the next step. Use a pipette to repeatedly blow the bottom of the mold to loosen the cells attached to the slide due to centrifugation and fall off, forming a cell suspension; the number of cells detached is controlled under a microscope. The method is: take 10μl of cell suspension, drop it on a clean slide, cover it with a coverslip, and count it directly under a microscope with a 40x objective lens. The number of squamous cells is qualified if it is greater than 10 (that is, the number of cells in each μl of suspension is ≥1). Otherwise, continue to blow until the requirement is met. Pour the cell suspension and the fixative into the same large bottle to obtain a mixed solution from 200 to 250 samples, with a liquid volume of about 700ml.

[0061] Place the large bottle of mixed solution on an oscillator and start a weak oscillation to allow cell fragments lighter than normal cervical epithelial cells to precipitate and float;

[0062] During the shaking process, use a pipette to suck away the upper half of the fixative in the bottle from the surface of the liquid; add the same amount of liquid-based cytology preservation solution; continue shaking, pipetting, and replenishing three times in a row. After the last time of sucking away the upper half of the liquid, no more replenishment is done. After standing for about 10 to 12 hours, a visible cell layer is obtained at the bottom of the bottle.

[0063] Gently aspirate all the liquid above the cell layer with a pipette and discard it;

[0064] Use a pipette to gently aspirate about one-third of the cell sediment from the cell layer and discard it;

[0065] Aspirate about one-third of the cell layer as quality control cells and place them into a bottle containing 250ml of liquid-based cell preservation solution, which is the stock solution for later use;

[0066] Take a certain amount of stock solution and prepare slides for testing according to the routine liquid-based cytology testing process of the pathology laboratory; evaluate the number of cervical squamous epithelial cells after preparation, and add liquid-based cell preservation solution to the stock solution in a certain proportion according to the number of cells on a single slide for dilution and adjustment.

[0067] Take the debugged stock solution and repeat the above steps until the number of cervical squamous epithelial cells on a single slide reaches between 8,000 and 12,000, and the overlap rate between cells is less than 20%. This is the final quality control product, 500 to 600 ml, which can be used for 170 to 200 quality control tests.

[0068] Repeat the above steps to obtain 250 ml of each of the four types of quality control products.

[0069] The quality control product of the "≤30 years old segment" is named quality control product A, the quality control product of the "30-50 years old segment" is named quality control product B, the quality control product of the "51-60 years old segment" is named quality control product C, and the quality control product of the "60 years old ≥ segment" is named quality control product D. The four types of quality control products together form a quality control product box.

[0070] Stability evaluation of quality control products: According to the detection steps of the embodiment, the detection was carried out continuously for 20 weeks, with quality control products being tested once a week. Each time, four types of quality control products were tested simultaneously to evaluate the stability of the quality control products. The results are shown in Table 1.

[0071] Table 1

[0072]

[0073]

[0074]

[0075]

[0076] The data in the above table indicate that the quality control product of the present invention has a longer shelf life and higher stability.

[0077] 3. Use of quality control products in testing:

[0078] Subsequently, the above-mentioned quality control kit was used to conduct the test according to the testing process of cervical thin layer liquid-based cytology. The specific process is as follows.

[0079] Step 1: Take one portion of each of the four types of quality control products (3.5 ml each) that is equal to the amount of clinical test samples, number the samples according to the requirements of the test items, and randomly and dispersedly insert the quality control samples into the clinical test samples.

[0080] Step 2: Quality control samples and clinical test samples are tested simultaneously:

[0081] Shake: 30 samples are placed in a shaker for 6 minutes.

[0082] Sample addition: Take 30 precipitation molds, add cleaning solution to each until the height of the filter membrane, and pour the sample into the corresponding precipitation mold in sequence until the height of the sample layer is two-thirds;

[0083] Sedimentation: Place the specimens in the centrifuge in order, balance them, set the centrifuge speed to 2500 rpm, set the time to 6 minutes, and perform centrifugal sedimentation.

[0084] Collect the slides: After the centrifugation is completed and the centrifuge stops, obtain the sedimentation mold and transfer it to the water tank. Disassemble the sedimentation mold, take out the film, and slowly immerse the film in running water for 3 to 5 seconds to obtain 30 cell smears.

[0085] Re-fixation: Place the cell smear into a staining rack and place the staining rack in 95% ethanol solution for re-fixation for about 2 minutes.

[0086] Staining: Soak the fixed smear in clean water for 2 minutes, then perform Papanicolaou staining, and then perform a series of operations such as dehydration with gradient ethanol, transparentization with xylene solution, and sealing with neutral gum.

[0087] Step 3: After sealing, all smears are submitted to pathologists for review and evaluation:

[0088] The pathologist will first review the quality control sample smear and conduct a quality control assessment. The assessment includes: the number of cervical squamous epithelial cells, the cell overlap ratio, whether there are abnormal cells, whether the nuclear staining is satisfactory, whether the cytoplasmic staining is satisfactory, whether there is cell shedding, whether the staining background is clear, etc.

[0089] The results of the quality control smear are used as follows:

[0090] If the number of cervical squamous epithelial cells on the quality control slide is less than approximately 8,000, it may be that the sedimentation time on the machine is insufficient or the sample volume is insufficient. The corrective measure for the former is: "Check whether the centrifuge setting is 2,500 rpm and the time is 6 minutes. If not, make corresponding adjustments." The corrective measure for the latter is "Retrain the sample loading personnel to ensure that the sample loading volume meets the requirements."

[0091] If the number of cervical squamous epithelial cells is greater than 12,000, it may be that the sedimentation time on the machine is too long. The corrective measure is to "shorten the centrifugation time";

[0092] If the overlap between cells is greater than 20%, it may be due to improper oscillation. In this case, the corrective measures are: "Increase the oscillation frequency setting or increase the oscillation time;

[0093] If abnormal cells are found, it may be that the staining reagent is not pure enough or has been contaminated. The corrective measures are: "Replace new staining reagents, or filter the existing reagents before use";

[0094] If the staining differences of the four types of quality control products are not obvious, the staining solution may be expired or improperly prepared. The corrective measures are: "Replace new staining solution or re-prepare the staining solution."

[0095] If any of the four types of quality control products show cell shedding, it may be due to instrument failure or excessive manual force. The corrective measures are: "Check whether the centrifuge and staining machine are in good condition; observe whether the operation method of the slide collector is standard.

[0096] Summarize and organize all quality control smear evaluation results of the day to find out their common problems and differences, so as to conduct an overall indoor quality control evaluation for the day.

[0097] To ensure the accuracy and reliability of the test results, the quality control products need to be noted: before starting the test, the quantity of quality control products required for the day should be divided and placed at room temperature; each reagent used in the testing process is batch-verified to ensure the best test results.

[0098] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for preparing a quality control product for cervical liquid-based cytology, characterized in that: The following steps are involved: Quality control sample selection; Quality control samples are broken up, filtered, and washed; Quality control sample fixation; Preparation of quality control cell suspension and assessment of effective cell number in suspension; Quality control cell pooling: Pour the cell suspension directly into the same large bottle together with the fixative to obtain a mixed solution from multiple samples; Remove cell debris sediment: Place the mixture on a shaker and start weak shaking to allow cell debris lighter than normal cervical epithelial cells to precipitate and float. During the shaking process, remove the upper half of the fixative in the bottle and add the same amount of new fixative. Continue shaking, aspirating, and replenishing three times. After the last aspiration of the upper half of the fixative, do not replenish it. After standing, obtain a visible cell layer at the bottom of the bottle. Obtain quality control cells: aspirate all the fixative above the cell layer and discard it; aspirate the cell sediment in the upper third of the cell layer and discard it; aspirate the middle third of the cell layer as quality control cells and place them in a liquid-based cytology sample storage bottle as the stock solution for later use; Preparation of quality control working solution: After shaking the entire bottle of stock solution, take a certain amount of stock solution for slide preparation and testing. Evaluate the number of cervical squamous epithelial cells after preparation. According to the number of cells on a single slide, add liquid-based cell preservation solution to the stock solution at a certain ratio to dilute it. Repeat the above steps until the number of cervical squamous epithelial cells on a single slide reaches between 8,000 and 12,000, and the cell overlap rate is less than 20%. This is defined as a qualified quality control product. The quality control sample selection further comprises the following steps: 1) Preparation of cervical liquid-based cytology samples: Categorize multiple liquid-based cytology samples according to different age groups and prepare them for future use; 2) Cervical liquid-based cytology sample testing: Take liquid-based cytology samples containing the same classification for testing, obtain the test results, and keep them for future use; 3) Selection of quality control cell extraction samples: According to the same classification, multiple liquid-based cytology samples with the same test results are collected as quality control cell extraction samples for future use; 4) Assembly of the quality control sample precipitation mold: Use a non-adhesive pathology slide as the negative film, and assemble the filter membrane net, fixed mold and negative film that come with the liquid-based cytology project product to form a new liquid-based cytology precipitation mold. The upper half of the mold is the sample loading layer, the lower half is the cleaning layer, and the filter membrane net is used as the boundary in the middle for future use.

2. The method for preparing a quality control product for cervical liquid-based cytology according to claim 1, characterized in that: In the quality control cell extraction sample selection step, the number of cervical squamous epithelial cells contained in the test results is greater than 8,000.

3. The method for preparing a quality control product for cervical liquid-based cytology according to claim 1, characterized in that: The quality control sample breaking up, filtering and washing specifically include the following steps: 1) Pour the cleaning solution provided with the liquid-based cytology product into the cleaning layer of the mold, pour the sample to be extracted into the sample layer of the mold, place the mold in a centrifuge and centrifuge at high speed, then let it stand; aspirate the liquid in the sample layer of the mold, remove the mold filter membrane, and aspirate the upper third of the liquid in the lower half layer; 2) Repeat washing: Add physiological saline to the mold until the liquid level reaches two-thirds of the mold. Use a pipette to blow the bottom of the mold to mix the physiological saline and cleaning solution. Then place the mold in a centrifuge at high speed and centrifuge it. Let it stand. Aspirate two-thirds of the liquid on the mold. Then add the same amount of physiological saline. After blowing, centrifuge it. Let it stand and aspirate two-thirds of the liquid on the mold. This will obtain relatively pure quality control cells and cell debris sediment for use.

4. The method for preparing a quality control product for cervical liquid-based cytology according to claim 1, characterized in that: The quality control sample fixation comprises the following steps: 1) Preparation of quality control sample fixative: dissolve paraformaldehyde, sodium dihydrogen phosphate, and disodium hydrogen phosphate in distilled water, mix thoroughly, and allow to stand for later use. 2) Fixation of quality control samples: Add fixative to the mold until the liquid volume reaches two-thirds of the mold height, thus completing the fixation of quality control cells, precipitating cell proteins, inactivating cell zymogens, and cross-linking and fixing intracellular macromolecules, thereby blocking possible cross-adsorption or abnormal reactions between different individuals.

5. The method for preparing a quality control product for cervical liquid-based cytology according to claim 1, characterized in that: In the quality control sample selection step: a sample without blood, mucus, and impurities visible to the naked eye is selected, wherein the number of cervical squamous epithelial cells is greater than 8,000.

6. The method for preparing a quality control product for cervical liquid-based cytology according to claim 1, characterized in that: The preparation of the quality control cell suspension comprises the following steps: repeatedly blowing the bottom of the mold with a pipette to make the cells attached to the glass slide due to centrifugation fall off the glass slide to form a cell suspension.

7. The method for preparing a quality control product for cervical liquid-based cytology according to claim 1, characterized in that: The evaluation of the effective cell count of the suspension includes the following steps: taking the cell suspension, dropping it onto a clean pathology slide, covering it with a coverslip, observing it under a microscope, and counting the number of squamous epithelial cells contained therein. The qualified number is ≥1 cell per μl of suspension; otherwise, the bottom of the mold needs to be blown continuously to remove the attached cells.

8. The method for preparing a quality control product for cervical liquid-based cytology according to claim 1, characterized in that: The quality control products were refrigerated at 4°C to 8°C.

9. A quality control product for cervical liquid-based cytology prepared according to the preparation method of any one of claims 1 to 8.

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