COVID-19 Pooled Sample Testing:Improve sampling rate and reduce cost

Posted on 2021年9月18日2021年12月21日 by Dr. Lee

COVID-19 Pooled Sample Testing:Improve sampling rate and reduce cost.

With the advent of autumn and winter, the possibility of a new outbreak of COVID-19 is increasing.

COVID-19’s large-scale community screening is the main means to cope with the recent outbreak of small-scale epidemics at home and abroad.

At present, New Coronavirus’s mixed sample nucleic acid detection has become a routine method to effectively enhance the screening and detection of nucleic acid in community population.

The pooled sample test of covid-19 increase the sampling rate and meet the growing needs of low-risk populations.

Virus transport medium,disposable virus sampling tube

What is a Pooled Sample Test?

“mixed detection”, that is, nucleic acid test of Pooled Sample.

On the one hand,it is a method to sample several people, such as 3 or 5 or even 10, and then put them into the same virus sampling tube.

On the other hand,pooled Sample means combining the same type of specimen from several people and conducting one NAAT laboratory test on the combined pool of specimens to detect SARS-CoV-2.

What is the significance of nucleic acid test in Pooled Sample?

COVID-19 Pooled Sample Testing Advantages

Because a virus sampling tube only puts one person’s sample, the cost will be very high, and the detection time is long, which is not suitable for large-scale nucleic acid detection.

In principle, the single sample sampling mode is only applicable to high-risk areas and key populations.

In order to improve sampling efficiency, shorten sampling time and reduce sampling cost. Multi Country selection of Pooled sample test scheme.

For example, when 5-in-1 mixed sampling test is used, the result is negative, which means that all five people are negative.

On the contrary, once positive or weak positive is found, it will be traced immediately.

Re collect single tube swabs for review, and then determine which of the 5 people is positive.

Therefore, the cost of 5-in-1 mixed mining is relatively low.

This also caused the 5-in-1 mixed sampling mode to be five times faster than the previous mode of using a virus sampling tube for a human sample.

One of the biggest disadvantages of sample merging is the decrease of associated test sensitivity.

Analyzing multiple samples in a single reaction effectively improves the flux, but it also dilutes a single sample and may reduce the weak positive signal from outside the detection limit.

In short, pooled sample testing is mainly used for large-scale screening to check asymptomatic coronavirus infected persons. It is suitable for large-scale testing projects such as schools, factories, units and urban areas. It has the advantages of efficient screening and resource saving.

Although reduced detection sensitivity is acceptable for screening services in asymptomatic populations.

However, When providing diagnosis for high-risk or symptomatic patients, we must give priority to the accuracy of the results.

The special preservation tube for Pooled Sample test uses medical grade PP as raw material, unique structural design and manufacturing process to prevent liquid leakage. And has the characteristics of high temperature resistance, high pressure resistance and high-speed centrifugation resistance.

Cell medical (Dongguan) Co., Ltd. produces virus sampling tubes of various specifications, both inactivated and non inactivated, disposable virus sampling tubes, pooled sample sampling tubes.
such as 1ml, 2ml, 3ml, 5ml, 10ml and other specifications.

Located in Guangdong Province, in China,with complete qualifications.

Contact information required.E-mail:flockedswabs@gmail.com

Pcr test nasal swab and an antigen test difference for covid 19

Posted on 2021年9月18日2022年3月22日 by Dr. Lee

Pcr test nasal swab and an antigen test difference for covid 19

What is COVID-19?COVID-19 is an epidemic disease caused by SARS-CoV-2. An acute respiratory infectious disease broke out at the end of 2019. So far, WHO has been making the latest tracking report on the new pneumonia on the Internet every day.

What are the current methods of COVID-19 test?

Virus detection includes two types: nucleic acid amplification test (NAAT) (PCR test) and antigen test.

Antibody tests (also known as serological tests) can prove whether you have been infected in the past.

What is the COVID-19 PCR test?

PCR (polymerase chain reaction): similar to the natural replication process of DNA, its specificity depends on oligonucleotide primers complementary to both ends of the target sequence.

Basic principle: the basic principle of PCR technology is similar to the natural replication process of DNA. Its specificity mainly depends on the oligonucleotide primers complementary to both ends of the target sequence. It consists of three basic reaction steps: denaturation, renaturation and extension.

PCR test sample collection method include:

If the sample contains a virus, the researchers will extract its RNA.

Why use the PCR test ?

PCR nucleic acid examination is a direct detection of COVID-19 RNA in human body by sampling from the nasal cavity. The structure of virus is composed of DNA or RNA combined with external lipid protective capsule. Therefore, direct detection of virus DNA itself is the most accurate, fastest and effective new detection method. PCR nucleic acid test can detect infection immediately after the human body obtains the virus, and the accuracy is much higher than antibody test.

ABOUT PCR TEST_Pcr test nasal or Throat swab sampling

How does the PCR test nasal swab work?

Nasopharynx swab is to wipe the secretion of the patient’s nasal cavity or pharynx. And then make the secretion into smear for examination and bacterial culture to clarify what bacterial infection is in the patient’s nasal cavity and pharynx.

Nasal swab sampling procedure

1. Keep the patient’s head still and remove the secretions on the middle surface of the anterior nostril;

2. Gently and slowly insert the swab through the nasal cavity to the nasopharynx;

3. After encountering resistance, it reaches the posterior nasopharynx and stays for several seconds to absorb secretions;

4. Gently rotate and take out the swab and place it in the transport medium;

5. For the swab used for virological test, immerse the swab head into the virus delivery medium, discard the tail, and tighten the tube cover;

If it is necessary to collect from both nostrils, the sampler should use the same swab.

How does the antigen test work?

Rapid antigen detection can play an important role in guiding patient management, public health prevention and control decision-making and covid-19 monitoring.

It is especially valuable for grass-roots areas that may hinder clinical diagnosis and control due to lack of nucleic acid detection capacity or long detection time.

According to WHO, high specificity based on antigen detection indicates that the positive results indicate new crown virus infection.

For patients within 9 days of onset, sampling personnel can use antigen detection as a diagnostic test.

Especially for the staff of medical institutions, inpatients and visitors in the epidemic area.

When nucleic acid detection cannot be effectively implemented, antigen detection can be used as an important screening method.

Rapid antigen test sampling procedure.

Rapid antigen test sampling process

Generally speaking, nucleic acid detection: it has high requirements for laboratory environment, detection personnel and instruments. The detection has high sensitivity and good specificity.Generally, we can get the results in 2-3 hours.

Antigen detection: it has low requirements for the laboratory. For early screening and early diagnosis. It is suitable for large-scale screening in grass-roots hospitals. we can obtain the results within 15 minutes at the fastest.

At present, PCR test nasal swab is widely used, and the sensitivity and specificity of antibody / antigen detection reagents are still limited.

Each has its own emphasis and cannot replace each other. We should combine multiple virus detection methods.

It can effectively shorten the detection window period and improve the positive detection rate.

Disposable virus sampling media 10ml transport tube for sample collection

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

Disposable virus sampling media with 10ml transport tube for sample collection.

Product Description

Disposable virus sampling tube

Product name:Disposable virus sampling tube.Keyword:sample collection kit,virus sampling medium.

Function:sample collection,storage,transport virus.

OEM/ODM: accept.

Place of Origin: Guangdong, China.

Disinfecting Type: EO.

Sampling tube specification

Properties: Medical Materials & Accessories.

Tube Volume: 5/10ml.

Stock: yes.

Shelf Life: 12 months.

Material: PP.

Quality Certification: ce,MSDS.

Instrument classification : Class I.

Virus DNA / RNA sample preservation solution (inactivated or non)

I believe that my friends must be very curious when they first came into contact with this term. Virus DNA / RNA sample preservation solution, also known as cell preservation solution, virus transport medium or disposable virus sampling tube.

What is a virus transport medium?

First, the virus preservation solution is a liquid that immerses the sampling swab virus sample in the sampling tube and protects the detected substance (DND or RNA) of the virus.

It is mainly used for the collection, preservation and transportation of common virus samples such as New Coronavirus, hfmv, influenza virus and so on.

Researchers can use it to collect throat swabs, nasal swabs, or tissue samples from specific sites.

The samples are stored in a disposable virus sampling tube, which can be used for subsequent clinical experiments such as nucleic acid extraction or purification.

We divide virus transport media into two types, one is non inactivated and the other is inactivated.

The non inactivated type can protect virus protein and nucleic acid, preserve virus activity and facilitate culture and detection.

The inactivated type makes the virus no longer have physiological activity, lose infection and disease, and have fecundity, which can inactivate the virus.

Eliminate secondary infection and protect the safety of transportation and testing personnel.

Because the virus is a parasite, it cannot survive in vitro after sampling. If it cannot be detected in time, it needs to be stored in virus preservation solution.

In order to protect the security of virus detection environment and detection personnel, our virus inactivation preservation solution comes in handy.

Some friends may wonder if the inactivated type will inactivate the virus? How can we check it?

Don’t worry, the purpose of using inactivated preservation solution is to lyse nucleic acid.

Release nucleic acid and then detect nucleic acid through subsequent real-time fluorescent RT-PCR to judge whether the sample contains virus characteristic nucleic acid, that is, whether it is infected with virus.

The virus has a single structure and contains only one nucleic acid and protein. Therefore, the virus is detected when the characteristic nucleic acid is detected.

Then some friends will ask, since the detection is so simple, why do you need virus preservation solution? What role does it play?

Usually, after virus sampling, not all samples can be transported and stored at the sample collection place.

Therefore, we need to transport and retain the collected virus swab, otherwise the virus nucleic acid will degrade quickly and the nucleic acid cannot be detected.

Therefore, we need to add preservation solution to the sampling tube to prevent the virus nucleic acid from being degraded so quickly.

Cell Medical’s virus preservation solution allows viral DNA/RNA to be stored and transported at room temperature for 1 week without degradation.

After extraction using most commercial kits, the obtained DNA/RNA is of high quality and high yield, and can be used for various gene testing and analysis experiments, such as PCR and qPCR, while saving transportation costs.

Cell Medical’s inactivated virus storage fluid uses a small volume storage fluid compared to the large volume storage fluid of a traditional virus sampling tube, which avoids excessive dilution of the collected samples and increases detection sensitivity.

And our inactivated virus storage solution is so easy to use that you can take samples at home.

Moreover, our inactivated virus preservation solution is simple and convenient to operate. You can take samples at home.

Well, if you have anything you don’t understand or want to consult, please leave us a message.

We will have a professional doctor and my little brother will let you answer.

About us

Cell medical (Dongguan) Co., Ltd. is a professional manufacturer and supplier of sampling swabs and virus sampling tubes.

We produce flocked swabs, VTM kits, virus transport media, with multiple automatic production lines.We support custom production, OEM and so on, and develop products with customers.

Welcome to consult us.

Email:flockedswabs@gmail.com.

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

Mini flocked nose swab china factory and manufacturers

Posted on 2021年9月16日2021年12月21日 by Dr. Lee

Mini flocked nose swab china factory and manufacturersCell medical (Dongguan) Co., Ltd., flocked swab adopts vertical nylon fiber, which has stable and reliable performance and good adsorption and elution ability. Flocked swabs optimize sample collection and elution into the transmission medium. The swab also has a molded breakpoint that allows you to safely and easily disconnect the cotton swab. Our company provides multiple breakpoint options for different pipes.We can customize swab mold, swab packaging, sterile packaging and swab OEM services.

Mini flocked nose swab Specifications

Mini flocked nasal swab

Swab Length: 145mm±5mm
Flocked Tip Length: 8mm
Swab Tip Diameter: 8mm±0.2mm
Breakpoint: 80/90mm
Packing: Individual Sterile Package
Certificate: CE/FDA/ISO
OEM/ODM: Support
GMP Factory: YES
Supplying Ability: 500,0000pcs/ day

Application: Nasopharyngeal Sampling Swab

Mateiral: 100% Medical Grade Nylon

Sterilization: EO

Certificate: ISO13485, CE, FDA, SGS, MSDS, TDS.

What’s the use of a flocked nose swab？

Nasal swab detection is a kind of nucleic acid detection, which is used to detect the presence of viral nucleic acid in the body. So as to determine whether the human body infected with COVID-19.

Nasal swab detection requires collecting cells deep in the throat of the tested person and placing them in a Petri dish for observation. Because New Coronavirus is mainly transmitted through the respiratory tract,if the human body is infected with COVID-19, there will be a lot of viruses in the throat. Therefore, it is a more accurate way to detect the existence of COVID-19 by detecting the cells in the throat.

What is the method of mini nasal swab collection?

① Please keep the patient’s head still and remove the secretions on the surface of the anterior nostril;

② use a flocked swab or other tools to the distance from the nostril to the root of the ear and mark it with your fingers;

③ insert the swab gently and slowly through the nasal cavity;

④ swab until the finger mark or stay for several seconds after encountering resistance to absorb secretions; (generally stay for 15-30 seconds, and then rotate gently for 3 times);

⑤ gently rotate the swab and put it into the virus sampling tube (transport medium); Break the swab tail rod along the breaking point and place it completely in the tube. Tighten the pipe cover.

⑥ If you need to collect from two nostrils, you should use another swab.

⑦ Send to the inspection room for inspection as soon as possible.

⑧ Note the information of the collected person to avoid confusion.

Mini flocked nasal swab sampling display

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.

China universal viral transport medium factory manufacturers

Posted on 2021年9月16日2022年3月30日 by Dr. Lee

China universal viral transport medium factory and manufacturers

Product specification

VTM KIT_Virus sampling tube

[common name]: disposable virus sampling tube, viral transport medium kits,universal viral transport media.

[specification and model]: 3ml / piece, 100 pieces / bag

[main structure and performance]

It usually consists of swabs and/or preservation tubes containing viral transport medium.

[scope of application]

For sample collection, transportation and storage.

[action principle]

After sterilizing the sampling tube, add virus stable components such as Hank’s base solution, which can maintain the activity of virus in a wide temperature range, reduce the decomposition speed of virus and improve the positive rate of virus isolation.

Description

Viral Transport Medium (VTM) allows the safe transfer of viruses, chlamydia and mycoplasma for further research, including conventional cell culture methods, diagnostic tests, and molecular biology techniques.

Commercially prepared viral transport media are available in a screw cap plastic tube containing buffered proteins (serum, albumin or gelatin) and antibiotics.

Viral transport medium composition

Our viral transport media contains Hanks Balanced Salt Solution (HBSS) with Calcium and Magnesium and contains heat-inactivated Fetal Bovine Serum, Gentamycin and Amphotericin B.

The composition and the manufacturing of the Viral Transport Medium follow the WHO and the CDC recommendations.

[contraindications, precautions, warnings and suggestive instructions]

1. After sampling with a virus sampling tube, the sampler shall submit it for inspection as soon as possible.

At the same time, the transportation personnel shall immediately transport the virus samples at a low temperature of 2-8 ℃.

The results showed that the virus samples could be stored at 2-8 ℃ for 48 hours; But for long-term storage, below – 20 ℃ and – 70 ℃.

If the sampler does not immediately transport at low temperature or store at the specified temperature after sampling. It will affect the positive rate of virus sample separation in the later stage.

2. prohibited to use it for the sampling of bacterial samples. The antibiotics contained in the sampling solution can inhibit bacteria.

3. forbidden to directly contact the collected patient, and forbidden to sample the patient after wetting the swab.

4. The sampling personnel shall collect virus samples in strict accordance with the sampling procedures to ensure the accuracy of sampling location. At the same time, the sampling intensity is uniform and appropriate, otherwise, it will affect the positive rate of virus isolation.

5. It is forbidden to use the expired or damaged product package.

6. The experimenter shall test the samples in a laboratory meeting the safety level.

Factory profile

Virus transport medium factories, Cell medical is a professional manufacturer of sampling swabs and disposable virus sampling tubes (viral transport medium).

The factory is located in Dongguan, China, with a daily production capacity of more than 1 million sets, aseptic filling technology and aseptic swab production technology.

China universal viral transport medium factory and manufacturers_Cell medical (Dongguan) Co., Ltd.

China VTM tube factory GMP factory_Cell medical (Dongguan) Co., Ltd.

Cell medical (Dongguan) Co., Ltd., vtm kit factories, vtm swab factory, produce flocked swabs, VTM kits, virus transport medium, universal viral transport media, with multiple automatic production lines.

We support custom production, OEM and so on, and develop products with customers.

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Email:flockedswabs@gmail.com

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.

Comparison of advantages of various testing methods of COVID-19

Posted on 2021年9月14日2021年9月15日 by Dr. Lee

advantages of various testing methods

The detection methods of COVID-19 mainly include nucleic acid detection, antibody detection and antigen detection. Due to the low detection rate of antigen, the SARS-CoV-2 detection mainly focuses on antibody and nucleic acid detection. Nucleic acid detection has the characteristics of early diagnosis, high sensitivity and specificity; However, antibody detection is convenient and rapid, which can be used as a supplementary means of nucleic acid diagnosis. Due to the limitations of “false positive” and “false negative” antibody detection, it is not suitable for general population screening such as returning to work, and school, nor for epidemiological investigation in low epidemic areas.

NAT Detection process

The detection procedure needs to go through five steps: sampling, sample retention, preservation, nucleic acid extraction and computer detection.

First, collect samples according to the instructions of the kit. The sample types include pharyngeal swab, nasal swab, sputum, bronchial lavage fluid, alveolar lavage fluid, etc.

Because RNA is easy to degrade, flocked swabs without RNase and storage tubes without RNase are used when collecting samples.

After obtaining the patient’s sample, it needs to be tested as soon as possible. If it cannot be tested immediately, it needs to be packaged at low temperature and sent to a special testing institution for testing.

After receiving the sample, the testing institution shall extract the nucleic acid from the sample. The nucleic acid extraction reagent shall use the nucleic acid extraction kit specified in the approved product manual.

Finally, fluorescence PCR nucleic acid detection, that is, machine detection. It takes 70-80 minutes to amplify the extract by fluorescence PCR.

Sample collection, oropharyngeal swab or nasopharyngeal swab

NAT Detection process Nucleic Acid Testing

Antibody detection

After the virus invades the human body, the human body will produce corresponding specific antibodies for defense.

According to different molecular structures and antigen specificity, scientists divide immunoglobulins into five categories: IgG, IgA, IgM, IgD and IgE.

After the antigen enters the human body for the first time, plasma cells secrete antibodies after a certain incubation period. IgM first appeared, but the antibody had short maintenance time, low concentration and low affinity. It lasted for several days to several weeks in the blood. It was a diagnostic index of acute infection; When IgM is about to disappear, the content of IgG reaches the peak. IgG appeared late, but its concentration was high, its maintenance time was long and its affinity was high. The positive serum IgG indicates the middle and late stage of infection or previous infection. But the antibody content increases rapidly in the short term, which may be several times to dozens of times higher than the original antibody content. It is mainly IgG, which lasts a long time in the body, and IgM rarely increases.

In this epidemic, the researchers studied patients with covid-19 and found that after the virus invades the human body, IgM antibody takes about 5-7 days to produce and IgG antibody takes 10-15 days to produce.

Antibody detection kits-advantages of various testing methods

Comparison of advantages and disadvantages of two different detection methods

Compared with the serological detection of antibodies, Nucleic Acid Testing can detect patients in the window stage.

Early detection of infected persons is the “gold standard” for COVID-19 detection, but it requires higher detection equipment or platform.

The high sensitivity RT-PCR instrument is expensive, and the laboratory cleanliness and operator requirements are higher. In addition, nucleic acid detection takes a long time. Considering the sample transportation and sample backlog, the results can be reported as soon as 24 hours.

Compared with nucleic acid detection, blood samples detected by antibody serology are easier to obtain. If the RNA of the virus detected by nucleic acid is the direct evidence of the existence of the virus, the antibody detection is the antibody stimulated in the patient’s blood, which is indirect evidence and has a suggestive effect on the clinic.

When nucleic acid detection is negative, adding IgM and IgG antibody detection can make up for the shortcoming that nucleic acid detection is easy to cause missed diagnosis.

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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.