COVID-19 Testing:PCR swab test,antibody test, and antigen test difference

Posted on 2021年9月17日2022年3月22日 by Dr. Lee

COVID-19 Testing :PCR swab test,antibody test, and antigen test difference.

PCR swab test（Nucleic acid test） and antibody / antigen detection are important means to confirm COVID-19, and also one of the important processes for patients to diagnose. But do you know what their detection principle is? What are the sample types? What is the inspection process and what are the problems?

COVID-19 nucleic acid test

Nucleic acid detection has the characteristics of early diagnosis, high sensitivity and specificity. At present, real-time fluorescence quantitative RT-PCR is the most widely used technology. PCR swab testing is a very effective way to identify SARS-COV-2.

1. Principle of COVID-19 test kits?

The researchers used sampling swabs to collect samples of the virus, targeting the unique gene sequence of the virus.

By PCR amplification of the virus sample, the target DNA sequence we selected increased exponentially.

Researchers can combine the amplified DNA sequence with pre added fluorescent labeled probe fragments to generate fluorescent signals.

The more target genes amplified, the stronger the cumulative fluorescence signal.

In Virus-free samples, no target gene was amplified. Therefore, researchers can not detect enhanced fluorescence signals.

That is, we do not carry COVID-19.

Therefore, nucleic acid detection is actually to detect the accumulation of fluorescence signal to determine whether there is viral nucleic acid in the sample.

COVID-19 test kits_PCR swab test（Nucleic acid test）

2. What are the methods of covid-19 testing samples?

Generally, PCR nasal swab test, pharyngeal swab, nasopharyngeal swab, sputum, bronchial lavage fluid, alveolar lavage fluid, etc.

Sampling swab consists of a nylon flocked swab.what is a flocked swab?

3. Steps of PCR swab test for COVID-19.

At present, pharyngeal swabs are the main sampling method for the diagnosis of novel coronavirus infection. Correct sampling is the key to improve the accuracy of nucleic acid samples collected from pharyngeal swabs. What are the factors affecting the accuracy of nucleic acid samples collected from pharyngeal swabs? There are three main aspects:

Depth of throat swab collection?

How long is the throat swab in contact with the mucosa?

Pharyngeal swab sampling “dot to dot” or wipe?

(1) Oral and pharyngeal swab collection tips

1. Sampling position: sit or semi-sit in decuffine position, with head slightly raised and mouth open, and head resting on the wall or against the back of the chair.

2. Standard sampling operation: Sampling personnel press the tongue of the subject with tongue depressors.

Pharyngeal swabs should be performed on both sides of the pharyngeal tonsil with “Quick wipe up and down” and on the posterior pharyngeal wall with “Quick left and right wipe” . Repeat 3 to 4 times.

Avoid contact with tongue, teeth and gums.

If you feel uncomfortable, quit, take a break, and try again.

Oropharyngeal Sampling flocked swab diagram

3. Precautions: Drinking water before oral and pharyngeal swab test will dilute the virus attached to the pharynx, especially drinking hot water will inhibit the activity of the virus.

In order to improve the accuracy of pharyngeal swab nucleic acid detection, we recommend that subjects do not drink water 15-30 minutes before the detection, so as to ensure the high accuracy of pharyngeal swab nucleic acid test.

(2) Nasopharyngeal swab collection tips

1.The sampling personnel shall collect samples from the side of the subject, and the subject shall pull down the mask to expose only his nostrils. If there is sneezing reflex, the subject can cover it with elbow or paper towel.

nasopharyngeal sampling diagram

2. Standard sampling operation: “one insertion, two stops and three rotations” — measure the distance from the tip of the nose to the front of the ear, half of the insertion length, usually about 4 cm for adults; Stay for 15-30 seconds to absorb nasopharyngeal secretions (depending on tolerance, minimum stay for at least 3 seconds; Rotate the nasopharyngeal swab for 1 week and slowly remove it.

The above is for the reference of sampling medical staff and patients, let’s work together to defeat COVID-19!

(3)Store samples

Dip the flocked swab head into the cell preservation solution(Virus transport medium), and tighten the tube cap immediately after breaking the tail;

Storage, put the sample tube into a sealed bag for timely inspection, and the inspection process requires a strict transportation environment, 2-8 ℃ storage.

(4) PCR TEST

Researchers operate nucleic acid extraction, extract inactivated virus samples for subsequent nucleic acid detection, and can use automatic equipment such as nucleic acid extractor.

Fluorescence PCR nucleic acid detection, that is, on the machine detection, the extraction of fluorescence PCR amplification reaction, needs 70-80 minutes.

process pcr test

4. What are the problems in nucleic acid testing?

False negative, due to improper sampling, improper specimen preservation, the use of different types of specimens and the use of different manufacturers of reagents may lead to nucleic acid test results “false negative” and missed diagnosis;

■ High requirements for detection equipment or platform, high sensitivity RT-PCR instrument is expensive, laboratory cleanliness and operator requirements are also high;

■ Nucleic acid testing is time-consuming. It usually takes 4-6 hours to complete an RT-PCR test.

Therefore, when the nucleic acid test is negative.

Relevant personnel can increase the detection of IgM and IgG antibodies to make up for the shortcoming that nucleic acid detection is easy to cause missed diagnosis.

COVID-19 Testing serum antibody test

Seven days after novel coronavirus pneumonia, the serum specific antibodies gradually emerged. The first is immunoglobulin IgM antibody, and then IgG antibody.

Thus, an elevated IgM antibody indicates a recent acute infection, and an elevated IgG antibody indicates a previous infection.

The biggest advantage of serological testing lies in its convenience and short detection time, which can effectively break through the limitations of existing detection technology on personnel and sites and shorten the detection time.

Novel coronavirus infection can be diagnosed in suspected cases if the serum specific IgM and IgG antibodies are positive, the IgG antibody changes from negative to positive, or the recovery period increases by 4 times or more than the acute period.

antibody test sampling process_COVID-19 Testing

1. Principle of serum antibody test kit?

The sample is added to the sample adding hole, and the sample will move forward along the detection card under the action of chromatography.

If the sample contains new coronavirus IgM antibody, the antibody will combine with colloidal gold labeled virus antigen to form a sandwich complex, which will show a positive result.

If the sample contains New Coronavirus IgG antibody, the antibody will bind to colloidal gold labeled New Coronavirus antigen and form a sandwich complex, which will show positive results.

The detection card also contains a quality control line (line C) to judge whether the chromatography process is smooth.

2. What are the sample types for serum antibody detection?

Generally, it is blood, including serum, plasma and whole blood.

3.COVID-19 antibody test in three steps

1. Open the aluminum foil bag of the test card, take out the test card and place it horizontally on the table;

2. Use a pipette to absorb serum/plasma/whole blood sample and add it to the sampling site. Then use the same method to absorb buffer drops and add them to the sampling hole of the test card.

3. Wait 15 minutes and read the result.

4. What are the problems in serum antibody detection?

■ False positive, individual patients with rheumatoid factors in the blood, heterosinophilic antibodies, autoantibodies, drugs and tumor cells, etc., easy to cause cross-reaction test, so occasionally false positive results;

■ False negative, due to the existence of a certain window period of serum antibody detection methods and the sensitivity of the detection kit will appear false negative results.

Therefore, serum antibody test is only used as a supplementary test for suspected cases of novel Coronavirus nucleic acid negative test and cannot be used as a diagnostic indicator for screening alone.

The combined use of serum antibody detection and nucleic acid detection can help to improve the detection rate of the disease and find out the confirmed patients as much as possible, which is more conducive to the control of the epidemic.

Interpretation of results of nucleic acid combined with IgG and IgM antibody detection

COVID-19 Testing antigen detection

A novel coronavirus antigen test can novel coronavirus be detected directly in human body samples. The diagnosis is fast and accurate, with low requirements for equipment and personnel.

antigen test kit_SARS-CoV-2

1. Principle of antigen detection kit?

SARS-CoV-2 , N, E and S protein antigens stimulate virus cells to produce specific antibodies.

2. What are the types of antigen test samples?

Usually samples from infected sites, e.g. oropharyngeal swabs, nasopharyngeal swabs, sputum, serum, plasma, etc.

3.COVID-19 antigen test in four steps

1. Drop the sample treatment liquid into the sample treatment tube;

2. Stir the sample swab and squeeze the tube wall until the specimen is fully eluted into the treatment solution;

3. Take out the detection card and add sample to the round hole;

4. Wait 15 minutes and read the result.

4. What are the problems in antigen detection?

■ False negative, higher sensitivity of antigen detection is required. Because New Coronavirus mainly affects alveolar and other lower respiratory tract. Therefore, sampling from the upper respiratory tract of nasopharynx and oropharynx cannot determine whether the pathogen can be detected. Or the sample contains a small number of viruses. All these factors may cause missed detection.

■ The preparation process is tedious and time-consuming. The development of the antigen kit requires the preparation of the recombinant antigen first, and then the preparation of monoclonal antibody in mice, which takes about two or three months. If the prepared antibody performance is not good, it needs to be prepared again, which takes another two or three months.

The joint detection

The COVID-19 Testing nucleic acid / antibody / antigen has different focuses and can not be substituted for each other. Multiple detection methods are combined and complement each other. Combine molecular biology and immune level detection to give play to their respective advantages and improve sensitivity and specificity. It can effectively shorten the detection window period, improve the positive detection rate, and provide double guarantee for all possible risk groups.

reference：Zhengtu Li，Yongxiang Yi et al. Development and clinical application of a rapid IgM‐IgG combined antibody test for SARS‐CoV‐2 infection diagnosis. J Med Virol.2020；1-7

China Sterile Sampling Swab factory and manufacturers

Posted on 2021年9月16日2022年3月22日 by Dr. Lee

China Disposable Sterile Sampling Swab factory and manufacturers

Guangdong Dongguan city Changan town comprehensive high-tech biotechnology company -Cell medical (Dongguan) Co., Ltd. , Nissan large amount of flocking sampling swab, Disposable Sterile Sampling Swab help COVID-19 prevention and control.

Our GMP factory _Cell medical (Dongguan) Co., Ltd.

Controlled environment Labor uniform strict control, Ensure DNA& RNA free product

Brief description

China Sterile Sampling Swab floced swab

Aseptic environment sampling swabs include aseptic environment sampling swabs, disposable sampling swabs, aseptic sampling swabs, disposable aseptic environment sampling swabs and disposable aseptic sampling swabs.

sterilization and packaging method

1. Sterilize the product with ethylene oxide

2. Adopted international paper plastic packaging convenient for sterilization.

3. Independent packaging, easy to use.

special storage conditions and methods

Stored in a cool, dry and clean environment with no corrosive gas at 2 ℃ ~ 30 ℃ and relative humidity of 40% ~ 90%.

Nasal swab: for medical institutions to collect virus and DNA samples infected in patients’ nasal cavity. Virus sampling swab: used for nose and throat sampling of respiratory and intestinal viruses such as influenza, swine influenza, avian influenza, hand, foot and mouth.

Product composition: ⑴ nylon flocked swab. That is, sterile sampling swab (for sampling, the release is up to more than 90%).

Product features:

① International paper plastic packaging convenient for sterilization.

② γ Ray sterilization to ensure sterility.

③ Each set of independent packing in the large packing box is convenient to use.

④Researchers can select different culture media (bacteria, viruses, mycoplasma, chlamydia) for different types of specimens.

China Sterile Sampling Swab (Cell medical ) advantages:

1. Collection swab features: the collection system adopts nylon flocked swab, which is non-toxic to microorganisms and can maximize the collection and release of samples.

2. A large number of clinical experiments show that compared with ordinary sterile cotton swabs, nylon flocked swabs have a better effect on the collection and transportation of clinical microbial samples.

Especially for those samples that cannot be submitted for examination in time and placed for too long.

Advantages of flocked swabs:

① The unique jet nylon fiber implantation technology increases the collection and release of specimens.

② The total length of the swab is 15cm, and the plastic rod has a unique breakable design.

③ Flocking swabs can collect more target analytes.

④ There is no residual specimen, so the specimen processing process can be accelerated.

⑤ Swabs are sterilized and packaged separately. Aseptic swabs packaged separately.

Respiratory Specimen Collections

Posted on 2021年9月15日2022年3月22日 by Dr. Lee

Respiratory Specimen Collections

Today, with the increasingly severe international COVID-19 epidemic, the correct collection of respiratory samples has become an important prerequisite for ensuring the accuracy of nucleic acid detection results.

However, how to correctly collect respiratory samples? Cell medical (Dongguan) Co., Ltd. summarizes as follows:

Why should respiratory tract samples be collected standardized and correctly?

1. Clear diagnosis;

2. Observe the condition and treatment effect;

3. Guide the formulation of treatment measures;

4. Sample quality directly determines the reliability of test results.

What are the types of respiratory samples?

1. Upper respiratory tract samples (including swabs, nasal specimens, nasopharynx extracts, pharyngeal gargle and nasal lotion, etc.);

2. Lower respiratory tract samples (such as sputum, tracheal aspirate, lung lotion, etc.);

When is the best time to collect respiratory samples?

Respiratory tract samples were collected as soon as possible after symptoms appeared;

Collect as much as possible within 72 hours of the patient’s fever;

Try to collect before the use of antiviral drugs;

If possible, collect multiple times in multiple days;

What sampling tools are needed to collect respiratory tract samples?

1. Virus sampling kits, including flocked swab, virus sampling tube, virus transport medium, etc;

2. Refrigerated transport box;

3. Personal protective equipment: protective mask (N95), protective glasses.

How to collect respiratory tract samples?

Oropharyngeal swab sampling process:

Oropharyngeal swab sampling pictures

1. The sampler first let the patient sit down, then let the patient tilt his head back and open his mouth.

2. Press the front 2 / 3 of the patient’s tongue with a tongue depressor, and wipe the posterior pharyngeal wall and bilateral tonsils with a nylon flocked swab for 3-5 times to avoid touching the tongue.

3. Take out the rear sampling tube, break the plastic handle at the contact part of the hand, soak the swab into the sampling solution, and tighten the tube cover.

Nasopharyngeal swab:

Note : do not use too much force, but try to be as deep as possible, usually more than 5cm, stay for several seconds to absorb secretions, gently rotate and take out the swab, place the sampling tube, break the plastic ellipse at the contact part of the hand, and soak the test piece into the sampling solution, Tighten the pipe cover.

Respiratory Specimen Collections preservation requirements

Those that can be detected within 24 hours can be stored at 4 ℃ and frozen at – 70 ℃ for more than 24 hours.

Swab test | Disposable virus sampling swab

Posted on 2021年9月15日2021年9月15日 by Dr. Lee

Swab test | Disposable virus sampling swab

Disposable virus sampling swab, I believe you are no stranger in the past two years. Because most of the detection tools used for nucleic acid test are disposable sampling swabs. Usually, we see most nasal swabs and pharyngeal swabs. But disposable virus swabs are not only useful for nucleic acid testing. What else can a disposable sampling swab do? Let’s get to know.

What can a disposable virus swab be used for?

In addition to nucleic acid detection, scientists can also use disposable sampling swabs for microbial collection. They are usually used for virus detection and research in hospitals or laboratories. Researchers use disposable sampling swabs to detect biological samples in natural cavities of human or animals. Such as throat, nose, mouth, vagina and so on. It is necessary to collect oral epidermal cells and nasal virus samples with a sampling swab, store the cells and samples in the sampling tube and transfer them to the laboratory for examination.

Oropharyngeal swab sampling

Operation (use) method of disposable sampling swab:

Take pharyngeal swab as an example:

① Tear open the packaging bag of the disposable sampling swab and take out the disposable sampling swab from the bag;

Note: please do not let the disposable sampling swab touch the place outside the throat to avoid pollution.

② Put a disposable sampling swab into the mouth and quickly wipe the palatal arch and throat (or lesion) on both sides

③ Take out the swab, put it into the disposable virus sampling tube, break the disposable sampling swab at the broken place and discard the tail;

④ Tighten the sampling tube, put the virus sampling tube into the biosafety bag and submit it for inspection in time.

Note: please do not shake the virus sampling tube excessively to avoid dilution and loss of samples. After sampling, do not touch other objects with a disposable sampling swab.

How to carry out COVID-19 nasal swab test?

The doctor shall wear protective clothing, mask, gloves and mask to let the patient take a proper position.

Gently insert the flocked sampling swab into the nose, rotate it for three times, take it out and put it into the sample tube with protective solution, and screw the cover. Then label it, write the date, and send it to the laboratory for nucleic acid test of nasopharyngeal swab.

What is a COVID-19 swab test?

Swab test, namely nucleic acid test. The substance test by nucleic acid is the nucleic acid of virus. Nucleic acid detection is to collect the presence of viruses in the respiratory tract, blood or feces of patients, and determine whether they are infected by COVID-19. Therefore, once detected as nucleic acid “positive”, it can prove that there is a virus in the patient’s body.

SARS-CoV-2 nucleic acid detection process.

The usual sample types include throat swabs, nasal swabs, sputum, bronchoalveolar lavage fluid, alveolar lavage fluid and so on.

The sampling personnel shall conduct PCR detection as soon as possible after obtaining patient samples.

After the testing institution receives the sample, the laboratory personnel shall extract nucleic acid from the sample. And the nucleic acid extraction reagent shall use the nucleic acid extraction kit specified in the approved product manual.

Disposable virus sampling swab material.

At present, because of its stable and reliable performance and excellent absorption and elution capacity, nylon flocked swabs are widely used in COVID-19 sampling.

Swab test result

Swab testing for novel coronavirus pneumonia usually takes 4-6 hours to produce results, while rapid examination takes 2-3 hours. However, the reagents used in each hospital are different, so the time of results is also different.

COVID-19 positive results：Maybe infected.After 24 hours of self isolation, the positive patients need to conduct swab test again.

If the two results are positive, the next step is to improve CRP, blood routine, chest CT and other tests to determine whether COVID-19.

When COVID-19 nucleic acid test is negative once, it should be combined with the clinical symptoms and epidemiological contact history of patients. Because a COVID-19 nucleic acid swab test is negative, it can not completely exclude the infection of COVID-19.

Is anal swab nucleic acid test more accurate than nasopharyngeal swab?

Posted on 2021年9月13日2021年9月13日 by Dr. Lee

Is anal swab nucleic acid test more accurate than nasopharyngeal swab?

Nucleic acid detection:generally carried out by sampling pharyngeal swabs in the nasal cavity and oral cavity.

Now began to increase the anal swab test, we are also curious about this test method. So, is anal swab nucleic acid detection more accurate than nasopharyngeal swab? How to sample for anal swab test?

Is the nucleic acid detection of anal swab more accurate than that of nasopharyngeal swab?

In the screening of New Coronavirus pneumonia, we mainly used the oropharyngeal swab nucleic acid test. Because the reason is convenient and quick, suitable for large-scale screening. The accuracy of nasopharynx swab for new crown nucleic acid detection is higher than that of oropharyngeal swab, but the human body feels uncomfortable.

In last year’s test, researchers found that many infected people had negative pharyngeal nucleic acid.But their anal swabs were still positive for longer.

The combination of the two in nucleic acid detection can improve the detection rate and reduce the proportion of missed diagnosis.

However, anal swab sampling is inconvenient and not suitable for large-scale screening and testing in the community.

For some asymptomatic or mild infections, the condition recovers quickly after infection. And the pharyngeal nucleic acid may not be detected in 3 to 5 days.

The researchers found that the duration of nucleic acid positive in feces or anal swabs of some infected people was longer than that in the upper respiratory tract.

Therefore, increasing anal swab nucleic acid detection can improve the detection rate of infected patients and reduce missed diagnosis.

Although nucleic acid detection has the advantages of high sensitivity and short detection cycle, it also has some disadvantages.

Different from the direct isolation of live virus from human body, nucleic acid detection adopts an indirect method, which may cause false negative.

Anal swab & test tubes

How to sample for anal swab test

1. Soak the swab in normal saline, insert it into the anus of 2-3 cm, wipe it from the folds around the anus, or rotate it gently in the anus. And then insert it into the test tube containing normal saline.

2. For fecal swab culture, all the above operations require the use of sterile equipment and the swab into a sterile test tube.

Iclean nylon flocked swab

Posted on 2021年9月11日2021年12月21日 by Dr. Lee

Iclean nylon flocked swab

Product purpose:

Iclean nylon flocked swab is ideal for bacteriological sample processing, virological cell culture, DFA test, rapid and direct test, enzyme immunoassay test, polymerase chain reaction and molecular diagnosis based test, as well as forensic identification.

For throat sampling of respiratory viruses such as influenza, swine influenza, avian influenza, hand, foot and mouth.

Iclean nylon flocked swab,View more

Characteristics of sampling swab products:

1. It has extraordinary water absorption capacity, which can increase the number of samples collected on its surface from 20% of traditional sampling swabs to 60%.

2. The release rate of the collected samples is more than 90%, so as to ensure the high reliability of the results.

3. Different preservation solutions were selected for different specimen types.

4. The plastic rod has a unique breakable design to facilitate specimen transportation.

5. Ethylene oxide sterilization, irradiation sterilization, independent packaging.

Iclean gene sampling series flocking DNA oral test pieces are specially used to improve the amount and quality of genomic DNA in oral test piece cells. Oral cell sample is a good non-invasive collection and detection method instead of blood. Combined with icleanhcy’s series of DNA separation and stabilization kits, it can quickly collect high-purity and complete DNA samples.

DNA flocking swab is suitable for human and animal use. It has advantages over other DNA samples in design. Its unique sample matrix and rapid release interface are more conducive to efficient cell collection and maximize DNA yield. The test piece has been sterilized with ethylene oxide and passed the detection of human DNA contamination.

characteristic

The unique test substrate greatly improves the yield of DNA;

Adult oral SWAB piece 1 to 10 μ g DNA;

It is a good alternative to blood collection;

Both human and animal can use it;

Simple and fast operation;

There are two types of single and double disinfection packaging to choose from;

application;

Genotype study;

Veterinary genotyping and diagnosis;

Parent child and genetic services;

Forensic and DNA population studies;

About us

Cell medical (Dongguan) Co., Ltd. produce flocked swabs, VTM kits, virus transport medium, with multiple automatic production lines.We support custom production, OEM and so on, and develop products with customers.

Email:flockedswabs@gmail.com

Sample collection swab :How much do you know about nucleic acid testing

Posted on 2021年9月10日2022年3月22日 by Dr. Lee

Sample collection swab:How much do you know about nucleic acid testing

The spread of the covid-19 is continuing worldwide. Although the global scientific and medical circles are making every effort to fight the epidemic, it is difficult to predict how the epidemic will develop in the future, and its impact on social development has appeared in many aspects.

Currently, COVID-19 cases are over 220 million.

In order to fully control covid-19, the general screening of local areas shall be carried out if necessary.

After identifying the detection object, how to detect it?

1、 What specimen to choose?

According to the recommendations of the American infectious diseases association, the following specimens were used:

Nasopharyngeal swab
Middle turbinate swab
Anterior nostril swab
saliva
Anterior nostril + oropharyngeal swab
Alveolar lavage fluid
Anal swab

The sensitivity of simple oropharyngeal swab may not be enough, so it is relatively easy to miss diagnosis.

The sensitivity of alveolar lavage fluid is the highest, but it is obviously not suitable for universal screening.

Nasopharynx swabs and other operations should also be standardized.

Improper operation may make the quality of collected samples not high, thus increasing the risk of missed diagnosis.

2、 Select the time of detection

It is very important for COVID-19 to measure RNA and choose the right time. One analysis included 7 studies, including 2 unpublished reports, to evaluate the detection efficiency of RT-PCR at different time points after exposure to virus :

On the day of exposure to the virus, the possibility of detecting viral RNA is almost zero;

On the fifth day after exposure, that is, the first day after infection, the detection probability was 62%

About the 8th day after exposure, i.e. the 4th day after infection, the probability of detection was 80%

On the 21st day after exposure, i.e. the 17th day after infection, the detection probability was 34%

In conclusion, exposure to COVID-19 may require multiple tests to avoid missed diagnosis. However, it is not recommended to repeat the test within 24 hours of the previous test; The interval between two tests shall be at least 24 hours.

After 28 days of exposure to the virus, if the infection has not been diagnosed, it is not necessary to continue the detection; At this time, it is almost certain that it is not infected.

Nucleic acid detection throat swab sampling process

The COVID-19 nucleic acid was novel coronavirus, which was collected from sputum or lower respiratory tract by real-time fluorescent RT-PCR. If positive, the new coronavirus could be diagnosed. This is the basis for the diagnosis of new type of pneumonia. In addition to detecting the nucleic acid of the virus, it can also detect whether the virus in the specimen is highly homologous with New Coronavirus. If so, it can be diagnosed as New Coronavirus pneumonia. The virus is highly infectious and has the characteristics of human to human transmission, but the virus is sensitive to temperature and sunlight and ultraviolet rays.

Sample collection, nasopharyngeal swab sampling

Sample collection, Oropharyngeal swab sampling

The flocked swab is the best raw material for sampling swabs.

reference

1，Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19, updated December 23, 2020. https://www.idsociety.org/practice-guideline/covid-19-guideline-diagnostics/ (Accessed on January 14, 2021).

2，Kucirka LM, Lauer SA, Laeyendecker O, et al. Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction-Based SARS-CoV-2 Tests by Time Since Exposure. Ann Intern Med 2020; 173:262.

COVID-19 sampling tools help SARS-CoV-2 precise diagnosis!

Posted on 2021年9月9日2021年9月9日 by Dr. Lee

COVID-19 sampling tools help SARS-CoV-2 precise diagnosis!

Cell medical (Dongguan) Co.,Ltd. monthly production of millions of virus sampling swabs and VTM kits helps epidemic prevention and control.

What are the covid-19 sampling tools？

Flocked sampling Swabs,VTM Kits,Viral Transport Medium,VIRUS Collection & Transport Kits,Saliva collection kit,Disposable virus sampling tube,Op swabs,Np swabs,etc.

Why use sampling tools？

At present, the global New Coronavirus epidemic has reached a critical stage. The most reliable means of rapid diagnosis is still positive for nucleic acid detection. There has been a great breakthrough in the diagnosis of COVID-19, but clinicians, especially the laboratory doctors, still face the following serious problems:

1. Safety of specimens

The majority of “angels in white”, especially the laboratory doctors, are always facing the risk of virus infection.

Although there are various protective equipment, the risk of infection will increase if we can’t ensure the safety of specimens. Therefore, it is very important to ensure virus inactivation and the safety of collected samples.

2. False negative test results

The existence of false negative puzzles the clinic and affects the accuracy of diagnosis. The biggest problem is sample collection and preservation. The New Coronavirus infection prevention and control program (Fifth Edition) has been published to collect nasal swabs, throat swabs, sputum, lower respiratory tract secretions, blood and feces. The incorrect way of collecting and storing samples will lead to the degradation of viral RNA and directly lead to the false negative test results.

Cell medical (Dongguan) Co., Ltd. provides the perfect solution for sampling tools.

√. Cell medical provides samples of swabs collected from various viral types including New Coronavirus (covid-19) and provides a perfect solution.

√ .It can quickly inactivate viruses including New Coronavirus, influenza A virus and many other viruses.

√ .preservation solution: preserve RNA to prevent degradation.Disposable virus sampling tube.

√ .safety guarantee: vertical design, sampling and preservation in one step to reduce personnel exposure.

Sampling steps of new virus collection tube

1) The collection personnel shall be qualified through biosafety training and have corresponding experimental skills. Requirements for protective packaging of sampling personnel: N95 and above protective masks, goggles, one-piece protective clothing, double-layer latex gloves, waterproof boot covers, etc. in case of direct contact with the specimen, the protective equipment shall be replaced in time.

2) Sample type: pharyngeal swab and nasal swab.

nasal swab_COVID-19 sampling tools

Pharyngeal swab collection method: wipe bilateral pharyngeal tonsils and posterior pharyngeal wall with a plastic rod swab with polypropylene fiber head

Nasal swab collection method: gently insert a plastic rod swab with polypropylene fiber head into the nasopalatine part of the nasal canal, stay for a moment, and then slowly rotate and exit. Take another plastic rod swab with polypropylene fiber head and collect the other nostril wall in the same way.

3) Specimen preservation: immerse the swab head into the tube containing virus preservation solution, discard the handle along the folding point of the sampling swab, and tighten the tube cover.

Notes

The tube containing virus preservation solution another name isvirus sampling tube.

Virus preservation solution is also called virus transport medium.VTM.

What is genetic testing?

Posted on 2021年9月9日2021年9月9日 by Dr. Lee

What is genetic testing?

Definition of gene

What we usually call genes is a collection of genes in human cells, called the genome.

Every cell in our body has a complete genome. Inherited from parents and passed on to children.

Genes make people different from animals, make families different from families, and brothers and sisters are similar but different.

These subtle differences often do not exceed 0.5% of genes.

But determine different appearance, personality, genetic characteristics, and our adaptation to the external environment.

Why genetic testing?

It must be noted that various human traits and diseases are the result of the joint action of genes and environment .

Genes only play a partial role in traits, and whether gene expression is also greatly affected by the internal and external environment.

Therefore, gene test reports can not be directly used as the basis for clinical treatment, and it is not advisable to judge the role of genes without individual environment.

On this premise, the gene test report still has a certain reference significance for understanding various characteristics of the human body.

Understand that they carry hereditary pathogenic genes

We can know whether we carry pathogenic genes through genetic testing. For example, people with a family history of genetic diseases, cancer and hypertension. According to the test results, adjust dietary health care and living habits to avoid the occurrence of diseases. If both pregnant couples carry the pathogenic gene of recessive disease at the same time. They can pay attention and conduct further investigation when preparing for delivery.

Select drugs correctly to avoid drug waste and adverse drug reactions

Due to genetic differences, individuals will respond differently to drugs. When taking the same kind of drugs, some people will feel very effective, while others will not only be ineffective, but also have toxic and side effects. When some people use certain drugs, they may also have drug allergy. Through gene testing, we can know everyone’s gene situation, which may play a guiding role in drug use to a certain extent. Again, the drug test report can not be directly used in clinic. The drug selection and use in the treatment of diseases need to follow the doctor’s advice.

Provide scientific health management

Many adverse environmental factors and bad living habits will make the human body more prone to diseases. People can understand the occurrence tendency of individuals in different diseases through genetic testing, and make corresponding life adjustment or intervention in order to reduce the risk and delay the occurrence of diseases.

What is the principle of gene testing?

To understand the principle of gene detection, we need to understand the following questions:

Reasons for gene testing

Each person’s human nucleus has 23 pairs of chromosomes, which are composed of DNA and ribosomal proteins. All chromosomes have 3.16 billion base pairs.

When the same base pair position changes (this situation is generally called single nucleotide polymorphism, or SNP), which has a certain impact on human genetics and health, this SNP is the locus in the gene report. At present, there are nearly more than 100 million known or named SNPs. Most of the differences between human DNA are SNP differences, which is about 0.5% of the total base pairs of human DNA. A large part of gene detection is based on SNP.

Samples for genetic testing

Normal human samples required for gene testing include saliva sampling and blood sampling. For different examination items, excreta sampling and cell slice sampling are also included.

Methods of gene testing

There are several ways to measure related base pair differences (SNPs): PCR, chip, exon, and genome-wide. The number of SNPs detected is dozens, hundreds of thousands, tens of thousands, and all SNPs.

Disposable DNA sampling flocked swab

Oral DNA sampling swab_flocked swab cm-98000

1.Specially designed for micro DNA samples at the crime scene, especially for micro samples such as sweat, semen, blood, dandruff, oral cells, etc.

2. It can quickly absorb a small amount of samples and has high release aging rate.

3. The front end is sharp enough to extract cells from the victim or suspect’s fingernails.

4. The swab has a breakpoint, which is convenient for the automatic extraction workstation to extract samples.

5. The whole swab is packed in a transparent plastic tube to avoid biological pollution.

Who can do genetic testing?

① People with family disease history;

② People with bad living habits;

③ People exposed to chemical pollution, heavy metal pollution, nuclear pollution and toxic and harmful substances for a long time;

④ Friends who pay attention to health;

Hello!

When many diseases are diagnosed, it’s too late. Do a good job in disease prevention to make us healthy for a longer time!

COVID-19 Testing: Method of collecting virus swab samples

Posted on 2021年9月9日2021年9月17日 by Dr. Lee

COVID-19 Testing: virus swab

According to New Coronavirus’s pneumonia diagnosis and treatment plan (trial version fourth), to diagnose suspected cases of New Coronavirus pneumonia, we need one of the following etiological evidence:

1. Respiratory tract specimens or blood samples were detected by real-time fluorescence RT-PCR for New Coronavirus nucleic acid positive.

2. Novel coronavirus is highly homologous to respiratory tract specimens or blood samples.

Therefore, novel coronavirus pneumonia is an indispensable part of the specimen collection. So, where to collect specimens? How to collect specimens? How can medical staff protect themselves during collection? What should I do after collection?

How to obtain a virus swab specimen?

We all know that the collection method of virus swab specimen is basically to use the swab to sample the infected place or part of the virus, and then put it into the virus sampling tube containing preservation solution without touching other places, so as to conduct virus detection later.

Specimen type:

1. Upper respiratory tract specimens: including pharyngeal swab, nasal swab, nasopharyngeal extract, etc.

2. Lower respiratory tract specimens: including deep expectoration fluid, respiratory tract extract, bronchial lavage fluid, alveolar lavage fluid and lung tissue biopsy specimens.

3. Blood samples: try to collect anticoagulants in the acute stage within 7 days after onset. The collection volume is 5 ml, preferably fasting blood.

4. Serum samples: try to collect double serum in acute stage and recovery stage.

5. Conjunctival specimens: conjunctival swab specimens shall be collected for cases with ocular infection symptoms.

6. Stool samples: Patients with diarrhea symptoms need to collect stool samples.

COVID-19 Testing: Common virus swab sampling methods

Methods of throat swab collection

Inform the patient of the purpose of examination, collection method and collection time. It is best to collect specimens before using antibiotics.

Objective: To study the clinical effect of the method

Secretions were collected from pharynx or tonsil for bacterial culture or virus isolation to assist in clinical diagnosis and treatment.

Prepare sampling supplies:

Disposable sampling swab, virus sampling tube, tongue depressor and biological bag

Operation method:

(1) Ask the patient to sit down, tilt his head back, open his mouth and make a “ah ~” sound

(2) The sampling personnel shall fix the patient’s tongue with a tongue depressor, and use a disposable pharyngeal swab to pass through the root of the tongue to the posterior pharyngeal wall, tonsil recess and lateral wall;

(3) Repeatedly wipe 3-5 times to collect mucous membrane cells or sputum

(4) . gently remove the swab to avoid touching the tongue, the suspension, the oral mucosa and saliva

(5) Put the swab into the virus sampling tube gently and vertically. The sampling personnel shall disconnect the tail of the flocking swab and leave the tail of the swab completely in the tube.Be careful that the swab does not touch the wall of the tube.

(6) . tighten the cap, mark it, and seal it in the biosafety bag.

(7) The sampling personnel shall send the samples to the laboratory for testing in time. If the sampling personnel cannot send the samples for inspection in time, they shall store them at low temperature

Methods: nasal swabs were collected

Nasopharyngeal swab_COVID-19 Testing: Method of collecting virus swab samples

(1) Ask the patient to sit down with his head slightly back and remove the secretion from the front nostril first;

(2)measure the distance from nostril to ear base with swab and mark with finger

(3)gently insert the swab into the nostril until it is marked or stopped when there is obstruction. Let the swab stay in the nose for 15-30 seconds, and then rotate it gently three times.

(4) slowly pull out the nasal swab and quickly put it into the virus sampling tube. Then break the swab, leave its tail and place it completely in the tube.

(5) tighten the cap, mark it, and seal it in the biosafety bag.

(6) If we need to collect from both nostrils, we should use a swab.

(7) It should be sent to the laboratory for testing in time. If it can not be sent for inspection in time, it should be stored at low temperature.

Generally speaking, COVID-19 testing: the main methods of collecting virus swabs are nasopharyngeal sampling and oropharyngeal sampling.

Is COVID-19 pneumonia more infectious than SARS?

The effectiveness of infectious disease transmission depends on its basic regeneration index. Novel coronavirus pneumonia is more infectious than SARS at present, with a basic regeneration index of SARS higher than that of SARS.

The novel coronavirus pneumonia is a new disease, and the population is generally immune. Everyone is susceptible and susceptible to infection. The incubation period of COVID-19 also has the ability to transmit, and it has longer infection time. The novel coronavirus pneumonia novel coronavirus pneumonia is also typical of the clinical symptoms, and asymptomatic infections are also contagious, so the infection of new crown pneumonia is higher than SARS.

About us

Cell medical (Dongguan) Co., Ltd. is a swabs manufacturer. We produce and sell virus sampling related products. Such as virus sampling flocked swabs, VTM kits and virus transport media, and have multiple automatic production lines. We support customized production, OEM, etc., and develop products with customers.