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Covid-Nucleic-Acid-Test

Covid Nucleic Acid Test Nasopharyngeal Swab Test

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This article
To talk to you in detail
Covid nucleic acid test!

But in the face of the “nucleic acid swab test”
This unfamiliar and familiar word
Do you have many questions?

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Do you want to do a nucleic acid test when you go back?

Will it be difficult to make an appointment for nucleic acid testing?

How long does it take to get the results of a nucleic acid test at the hospital?

Should I Swab My Throat or Nose for Rapid COVID-19 Tests?

To answer your questions.
Today.
I’m going to tell you.
Those things about nucleic acid testing.

01. What is nucleic acid detection?

At present, nucleic acid detection is the main method for laboratory diagnosis to determine whether a patient is infected with the new coronavirus. It can achieve early detection, early diagnosis, and early treatment. Real-time fluorescent PCR can be used to detect throat swabs, sputum or blood samples. to covid nucleic acid, or detected by viral next-generation gene sequencing.

simply put

Nucleic acid testing is done by

After collecting human secretions

Tested by the instrument

to see if we have the new coronavirus in our body

If so, the test result is positive

On the contrary, if it doesn’t, it’s negative.

02. How to test the COVID swab?

“Sir, oropharyngeal swab, nasopharyngeal swab, and anal swab, which one to choose?”

How do you do a nasopharyngeal swab?

Nasopharyngeal swabs must be performed with the patient sitting upright with the head in an upright position, as this allows for easy visualization and access to the nasal floor perpendicular to the central axis of the patient’s face.

Flocked Tip Swab Nylon Sterile Nasal Swab Stick

Flocked Tip Swab Nylon Sterile Nasal Swab Stick

Insert the swab into the patient’s nose and align it parallel to the nose and the base of the septum. As long as there is no obstruction in the nasal cavity, the swab continues to move in this direction until it reaches the nasopharynx, at which point the tester feels resistance.

Once the swab reaches the nasopharynx, a gentle rotation and two complete 360-degree rotations are recommended to allow secretions from this area to be absorbed.

Once the swab is removed from the patient’s nose, it is immediately inserted into a viral sample containing a viral transport medium. The handle of the swab extending through the opening of the vial was broken off to allow the tube to be closed.

So
Now that there are oropharyngeal swabs and nasopharyngeal swabs
Why add anal swabs?
To answer your questions
Let’s take a look at their respective advantages and disadvantages

The specific operation of the anal swab is as follows:

Soak a flocked swab in saline, insert it 2-3 cm into the anus, wipe from the folds around the anus, or rotate it gently inside the anus, and insert it into a test tube containing saline.

anal swabs

For fecal swab cultures, all of the above requires the use of sterile equipment and placing the swab in a sterile tube.

So
Now that there are oropharyngeal swabs and nasopharyngeal swabs
Why add anal swabs?
To answer your questions.
Let’s take a look at their respective advantages and disadvantages.

Oropharyngeal swab: relatively simple to operate, less irritating, suitable for large-scale screening. Therefore, the nucleic acid test of oropharyngeal swabs is mainly used in the screening of new coronary pneumonia for the epidemic-related population, which is used in the routine nucleic acid test clinic of the First Affiliated Hospital of NTU.

Nasopharyngeal swab: The technical requirements are high, the human body does not feel comfortable, and the accuracy rate is higher than that of the oropharyngeal swab. However, for some asymptomatic or mildly infected people, the condition recovers quickly after infection, and the pharyngeal nucleic acid may not be detected in 3 to 5 days.

Anal swab: high accuracy, reduce missed diagnosis. The study found that the duration of nucleic acid-positive feces or anal swabs of some infected persons is longer than that of the upper respiratory tract. Therefore, anal swab tests will be carried out for key groups such as isolation points or some imported overseas.

In conclusion.
The three swabs have different lengths.
If you have to test an anal swab.
Don’t be shy.
Whatever the swab,
It is a good swab that can accurately identify the virus.

 
How does a Covid Mouth Swab Test work?

How does a Covid Mouth Swab Test work?

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How does a Covid Mouth Swab Test work?

I went for a swab test for the new coronavirus the day before yesterday, and the result came out yesterday and it was negative. Some friends asked me, is the throat swab test painful? How to do it? What are the types of COVID-19 tests? What COVID-19 test is more accurate? Today, Dr Lee came to give everyone a popular science.

You can use a variety of tests to determine whether you have COVID-19. Some tests are collected by mouth swabs, and some are collected by nasal swabs or saliva. In the experiment, an oral flocked swab was used to collect samples from the oral cavity for oral inspection. This is different from a saliva test, which spits out saliva into a small container.

On this page, you will learn:

  1. What is a mouth swab? Painful? 
  2. How to do a mouth swab COVID-19 test
  3. What are the types of COVID-19 tests?
  4. What COVID-19 test is more accurate?

What is a mouth swab? Painful?

The COVID-19 test is the most important way to diagnose the new coronavirus. Nucleic acid is the genetic material RNA of the new coronavirus. The nucleic acid test is to check a certain segment of RNA. If it is positive, it means that you are infected with the new coronavirus.
According to different sampling sites, nucleic acid detection can be divided into many types, such as throat swabs, anal swabs, tracheal secretions, alveolar lavage fluid, and so on.
Among them, throat swabs are the most commonly used, and oropharyngeal or nasopharyngeal secretions are taken for laboratory tests.

Oropharyngeal swab, the inspection process is very fast, no more than 10 seconds, only needs to open the mouth, and the staff uses a cotton swab to take a sample in the oropharynx.

Covid Mouth Swab Test work

Covid Mouth Swab Test work

When sampling, there will be a slight pain, and when the throat is stimulated, there will be a feeling of vomiting.

But the feeling is not strong, and it will be fine for a while.

According to British colleagues, the nasopharyngeal swab is more uncomfortable, and the pain will be greater because the nasopharyngeal swab needs to be completely pricked into the nose. Learn more about nasal swabs Please click here

How to interpret the results of the Oral swab test?

Nucleic acid(COVID-19) testing usually produces results within 24 hours. If you check today, the results will be known the next day. The results are nothing more than two cases, negative or positive.

Does negative mean there is no infection?

It is not 100% certain, because nucleic acid testing has a certain probability of false negatives. For example, in the early stage of the disease, the virus content is very low, and it may not be detected, or the sampling is not taken properly, and the sensitivity of the detection reagents, operation Whether it is standardized or not, etc., are affected by many factors.

How to do a mouth swab COVID-19 test

How to use mouth swab

How to use mouth swab

There are different ways to do a COVID-19 mouth swab:

  • 1. The patient needs to sit with his head back, open the mouth, and then remove the nasal cavity and the secretions on the oral surface.
  • 2. The collector uses a special tongue depressor to fix the patient’s tongue, and then cross the throat with the collecting tool, and the tonsils directly to the position where the specimen is taken.
  • 3. After repeated wiping of the collection table, mucosal cells can be directly extracted.
  • 4. Take out the collected throat swabs. Be careful not to touch the oral mucosa, tongue and saliva secreted by the oral cavity during this process to prevent inaccurate test results.
  • 5. Put the extracted throat swab into a special device and transport it to the laboratory for examination.

You may need to take specific steps before the test so that the results are as accurate as possible. If you need to book an appointment, ask if there’s anything you should avoid on the day of your test. Some types of tests that use saliva require that you don’t eat, drink, smoke, brush your teeth, or chew gum 30 minutes before the test (FDA, 2020).

What are the types of COVID-19 tests?

In the UK, when diagnosing COVID-19, there are usually two main types of tests:

Molecular biology tests, such as PCR (polymerase chain reaction), are used to find viral genetic material.

Look for the antigen detection of the virus shell.

Either test can be done with a nasal swab or a mouth swab. Saliva can also be used for PCR detection (FDA, 2021a). Although saliva and oral swab tests may sound the same thing, they are actually slightly different. The saliva test requires you to spit into the tube, while the oral swab test is to wipe a sample in the mouth with a cotton swab.

Nasal mucosal secretions follow the same rules, but the difference is that you or a health care professional collect the sample from your nose instead of your mouth.

Another type of test is antibody testing (also called serological testing). These two data can’t tell you whether you are infected now but can tell you whether you have been infected before or if you have been vaccinated before. Antibody testing usually requires a blood sample.

What COVID-19 test is more accurate?

How to interpret the swab test results

Nucleic acid testing usually produces results within 24 hours. If you check today, the results will be known the next day. The results are nothing more than two cases, negative or positive.

Does negative mean there is no infection?

It is not 100% certain, because nucleic acid testing has a certain probability of false negatives.

For example, in the early stage of the disease, the virus content is very low, and it may not be detected, or the sampling is not taken properly, and the sensitivity of the detection reagents, operation Whether it is standardized or not, etc., are affected by many factors.

With the continuous optimization of detection methods and the continuous updating of reagents, the sensitivity of detection is now higher, and the probability of false negatives is lower than before.

If it is negative, there is a high probability that it has not been infected with the new coronavirus.

For some high-risk groups, close contacts, and suspected clinically highly suspected cases, one negative may not be enough, and two, three, or even multiple tests may be required.

Notice

Even if you have been tested before, COVID-19 testing is difficult to cope with. But the test should be able to relieve stress and not cause stress.
In any case, the knowledge of COVID detection technology is constantly changing. If you want to know if you want to be tested and how it works, we will help you at any time. Here is some information about oral swab COVID testing and other information to determine whether COVID-19 is COVID-19, you need to know.

About COVID-19 Testing Click to learn more

About COVID-19 Swab Test

About COVID-19 Swab Test

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About COVID-19 Swab Test

The new crown virus has mutated continuously.

From Delta to Omi Keron, the COVID-19 virus has continued to mutate, and the global epidemic is prevalent at a high level.

Canada announced that all entry personnel from all countries except the United States are required to be tested for the new coronavirus.

At this time, whether you are leaving the country or entering the country.

I even worry or doubt whether I have contracted the coronary disease.

Perhaps understanding the new coronavirus test has become a compulsory course for most people.

What is the new crown swab test, how to collect a nasopharyngeal swab?  Is nasal swab sampling painful?  If your test result is positive, what do we need to do?  Why do most virus tests choose to flock swabs? Is nasopharyngeal swab accurate? Should you be tested for nasopharyngeal swab samples?

We talked with Dr. Li of Cell medical to learn more.

What is the COVID-19 test and what are the test methods?

Nucleic acid detection (RT-PCR Test) method, antibody detection, and antigen detection.

A swab test simple, effective, and fast way to detect COVID-19.

Including nasopharyngeal swab testing and oropharyngeal swab testing.

Medical staff will use flocked swabs to take samples from the nose and throat and put them into the virus sampling tube.

There are two types of swab sample testing: molecular test (PCR) and antigen test.

How to perform a COVID-19 nasal swab test?

The COVID-19 nasal swab test involves inserting a 6-inch flock (a long stick with a very soft brush) into the cavity between your nose and mouth (nasopharynx).

The medical staff inserts the flocking swab into each nostril for about 15 seconds and rotates it several times to collect enough samples for testing.

The samples are then sent to the laboratory for testing, and our test results are usually known within or within the next day

Since the nasopharynx is in a sensitive position of the body, it will produce a lot of very strange sensations.

On the one hand, the swab is inserted deeply into your nose and it irritates the lacrimal glands.

At this point, you don’t know if you are moved to tears or you are crying in pain.

The nasal swab test is not very painful, but it is very uncomfortable. Some people may have nausea during the nasopharyngeal swab test. Nasal swab painful.

Because the swab will also touch the back of your throat, this reaction is normal.

Whether it is tearing or nausea, nasal swab testing is a common phenomenon.

Don’t worry, everything is normal.

Are there other types of COVID-19 swab test methods available?

Yes, an oropharyngeal swab is one of the options.

Of course, if you want to experience another feeling, an anal swab test is also a good choice.

But they are not as sensitive as the COVID-19 nasal swab test.

Israel’s development of the new coronavirus “saliva detection method” saliva detection still needs scientists to confirm on a larger scale. There is no conclusion yet, but it is promising.

In addition to nucleic acid testing for the detection of viral genetic material, there is also antigen testing.

Currently, nasal swab testing for COVID-19, including nucleic acid testing, is still the best choice.

How about the covid test kit at home? Are their results reliable?

The home covid test kit sounds very attractive.

Home covid test usually refers to individuals collecting samples of themselves or their family members through sampling swabs.

We put the collected samples in test tubes with a virus transport medium, and then transport them to the testing facility.

Although you can use the Home covid test kit to test COVID-19 safely and comfortably in your own home.

However, Dr. Li suggested that it should be carried out at a professional testing institution.

Because the quality of the samples we collect and the integrity of the samples during transportation will affect the sampling results.

How accurate is the nasal swab test for COVID-19?

How to obtain a precise nasopharyngeal swab specimen?

Polymerase chain reaction (PCR) uses a piece of DNA as a template.

Then, with the participation of DNA polymerase and nucleotide substrate, the DNA is amplified to a sufficient amount for structural and functional analysis.

Pcr nasal swab test can be said to be very sensitive.

Scientists use PCR technology to amplify a small amount of RNA in the sample into deoxyribonucleic acid (DNA) and replicate it until COVID-19 (if present) is detected.

The following may affect the accuracy of PCR nasal swab sampling.

1. Smoking, drinking or chewing gum 30 minutes before use may also interfere with the test results.

2. Touching the swab with the hand or other objects and using the tip of the cotton swab will affect the accuracy of the detection.

Of course, the professionalism of the most important sampling personnel, we have to choose a professional testing agency for testing. And professional VTM Kits.

What should I do if the new coronary pneumonia nasal swab test is positive?

Very bad news!

If the COVID-19 nucleic acid test is positive, a single room isolation treatment should be carried out immediately.

Consultation by in-hospital experts or attending physicians will conduct multiple tests.

Under the premise of ensuring safety, the patient is safely transferred to a designated hospital for diagnosis and treatment.

Don’t worry. You need to actively cooperate with treatment

Otherwise, life is likely to be in danger, and large-scale infections will also occur.

In addition, proper physical exercise should be carried out in life to enhance the individual’s immunity. Colds and fatigue should be avoided.

Don’t do strenuous exercise, so as not to aggravate the disease.

A friend around me was infected with COVID-19. But my nasopharyngeal swab was negative. Is there any way to confirm that I have had it or am I immune to it now?

Certainly.

Antibody test, also called serological test, can detect the antiviral protein IgM and IgG antibodies produced by your immune system in the blood.

What are the types of samples for serum antibody testing?

It is generally blood, including serum, plasma, and whole blood.

PCR swab test, antibody test, and antigen test difference (Please click here)

 

Covid Rapid Test Kit

Covid Rapid Test Kit

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Covid Rapid Test Kit

Good news, recently, Health Canada approved covid-19 rapid test equipment. From now on, this equipment can be used for virus testing all over Canada, and the results can be obtained in 15 minutes at the fastest!

The number of outbreaks in Canada has soared, and the pressure of virus testing has also soared! Ontario and other places once had to queue up for more than 4 hours to wait for virus testing.

This will help alleviate the increasing number of confirmed cases and the need for virus testing. Best of all, the rapid test device can be managed by trained professionals in pharmacies and other places, without having to test the results through the laboratory.

About Antigen self test kit.

Antigen self test kit sampling process-Covid Rapid Test Kit

Antigen self test kit sampling process-Covid Rapid Test Kit

At present, most covid virus tests in Canada are carried out in public health clinics, and then the samples are sent to the laboratory for analysis.

This process may take several days.

Bcause some cities are facing the situation that testing centers queue up for hours.

How much do you know about COVID-19 antigen detection technology?

In late spring and summer of 2020, the COVID-19 epidemic was initially resurgent beyond all expectations, and unexpectedly came back with a strong attitude.

“COVID-19” On August 26, 2020, in order to control the spread of the epidemic.Abbottswab.

In addition, the federal government will spend $760 million to buy 150 million copies of reagents and transport them to nursing homes and schools in about a month.

Antigen detection.

By the end of October 2020, with more similar tests under way and waiting for emergency approval.

Three more antigen test kits have obtained the emergency use authorization (EUA) of the US Food and Drug Administration (US FDA), and the total number has reached 7.

In addition, although the World Health Organization was unwilling to do so at first.

It also approved the use of two antigen detection kits following the emergency authorization of the U.S. Food and Drug Administration in September and October 2020.

In the invention and transformation caused by covid-19 pandemic, detection technology has become a hot spot of biotechnology and engineering innovation.

In addition, more extensive measures such as wearing masks, maintaining social distance, isolating and tracking contacts.

And faster and cheaper screening tests provided by Cell medical provide hope for people’s urgent need to combat this infectious disease and make progress.

Many places in the world that seemed to have controlled the epidemic in the early stage broke out again.

Which shocked public health experts and called on everyone to carry out rapid and frequent testing.

Covid 19 self test rapid antigen test.

According to a report recently released by the Rockefeller Foundation.

If only to meet the testing needs of primary and secondary schools and nursing homes.

The United States should complete 200 million rapid tests per month by January 2021.

Although people tend to detect with higher accuracy, antigen detection with accuracy of only 70% .

People can also find infected persons omitted from previous tests through frequent detection. And provide sufficient accuracy for continuous screening.

According to Mara g. Aspinall, a practical professor and medical diagnostic expert at Arizona State University (ASU) in Tempe.

The co-author of the report, the number of tests required to screen the entire U.S. population may be twice that required by schools.

“Now it’s time,” Aspinall said. “We have an agreement and testing reagents. I hope the community can reduce the spread of the virus and control the epidemic again.”

 

 

Flocked Nylon Swabs and Non-Flocked Rayon Swabs

Flocked Nylon Swabs and Non-Flocked Rayon Swabs

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Flocked Nylon Swabs and Non-Flocked Rayon Swabs

Flocked swabs are famous for their stable and reliable performance and excellent absorption and elution ability.

Type of sampling swab.

1. Polyester fiber, polyester or rayon head, plastic or aluminum handle swab: it is suitable for the collection of virological test specimens. Swabs with wooden handles should not be used for the collection of virological test specimens.

2. Cotton swab: it is suitable for the collection of vaginal, cervical and urethral samples for Mycoplasma test, but not for the collection of bacteria (especially caustic bacteria) and Chlamydia test samples.

3. Polyester swab: suitable for sampling virus and bacterial samples.

4. Flocked swabs: made of nylon fibers by proprietary spray technology, suitable for sampling respiratory viruses and fungal culture samples.

5. Calcium alginate swab: it should be used for the collection of Chlamydia and botulinum pertussis nasopharynx swab. However, it is not suitable for the sampling of lipid coated virus and cell culture, Neisseria gonorrhoeae and Ureaplasma urealyticum.

Specimen Collection Swab.

Why choose flocked material as sampling swab material? What are its characteristics？

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;

 

Quick covid test

Quick covid test |How does covid testing work?

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A new covid test at home has been authorized by the U.S. Food and Drug Administration (FDA) for emergency use (EUA).

Here’s what you need to know about testing at home.

How can I get quick covid test?

Cell medical’s covid test at home now has a prescription, which means Americans can get one from their health care provider.

If doctors suspect that their patient is infected with covid – 19 within the first six days of symptom onset, they can prescribe a rapid test.

Quick covid test Rapid Antigen Test Kit Nasal Saliva Test at home

Quick covid test Rapid Antigen Test Kit Nasal Saliva Test at home

How much does it cost?

Please contact us for more details.

How does testing work?

Rapid Antigen Test is a lateral flow test, a portable covid test that usually returns results faster than the widely used laboratory based PCR test.

It works by detecting nasal swab samples and provides positive or negative results within 10 minutes. The results appear on test strips exposed to nasal swab samples.

The FDA said flocked swab can be collected from people aged 8 and over, but if the tested children are less than 14 years old, it should be collected by adults.

How accurate is the test?

Cell medical claimed that the time when the positive results of the test matched the PCR test was 84.8%, and the negative results matched the PCR test were 99.1%.

FDA said that the negative test results of covid test do not necessarily exclude the possibility of covid – 19 infection.

“and should not be used as the only basis for treatment or patient management decisions, including infection control decisions.

“People who are negative and continue to experience COVID 19, have a fever, cough and / or shortness of breath, may still have SARS – CoV – 2 infection. Follow up care should be sought from doctors or medical staff. ”

Not all side flow tests require the use of prescriptions. On December 15, the FDA issued the EUA for the first outside counter flow covid test at home.

The covid – 19 family test also uses nasal swab samples to detect covid infection and works with people aged 2 years and older.

The FDA said that in the population with covid symptoms, the ellume test correctly identified 96% of positive samples and 100% of negative samples. In the population without symptoms, it collected 91% of positive samples and 96% of negative samples.

Similarly, the FDA said that the negative results of the test do not necessarily exclude the possibility of covid infection.

Broader prospects

According to CDC data, as of Monday, the United States had reported 47.5million cases of covid and 778,316 deaths.

The data also showed that 432 million people were vaccinated on Monday.

A stock photo shows a schoolgirl receiving a nasal swab sample.

A stock photo shows a schoolgirl receiving a nasal swab sample.

The covid test uses self collected swab samples.

But adults should take samples from children under the age of 14 and over the age of 8.

Nasal swab quick covid test.

 

How to do a Nasopharyngeal Swab

How to do a Nasopharyngeal Swab

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How to do a Nasopharyngeal Swab?

Nasopharyngeal Flocked Swab

Nasopharyngeal Flocked Swab

Nucleic acid detection is to collect Nasopharyngeal swabs, sputum or lower respiratory tract specimens, real-time fluorescence RT-PCR detection of New Coronavirus nucleic acid, if positive, can be diagnosed with New Coronavirus infection, which 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.

Nasopharyngeal swab price：Welcome to email:flockedswabs@gmail.com

Nucleic acid detection and collection method:

(nucleic acid detection nasal swab)

1. Ask the patient to keep his head still and remove the secretions on the surface of the anterior nostril. The collector can stand on the side of the collector to reduce occupational exposure caused by coughing and sneezing and relieve the collector’s pressure.

2. Measure the distance from nostril to ear root with a swab and mark it by hand.

3. Gently insert the swab into the nostril in the direction perpendicular to the nose (face) through the nasal cavity, with a sense of touching the wall until the finger touches the nose, keep the swab in the nose for 15-30 seconds, and then rotate it gently for 3 times.

4. Put the swab into the virus delivery medium, break the swab rod and place it completely in the tube.

5. Tighten the pipe cover, mark it, put it in a plastic bag and seal it.

6. Send the samples for examination in time

swab test nasal swab

swab test nasal swab

1. With the aid of tongue depressor, the collector opens his mouth and makes an “ah” sound. The palate is lifted up to expose the posterior pharyngeal wall. The swab crosses the root of the tongue to reach the pharyngeal stenosis lesion, and quickly wipe the palatal arch, pharyngeal and tonsil secretions on both sides.

2. The nasopharynx swab was put into the virus delivery medium, and the auxiliary tube cover broke the swab rod to make it completely placed in the tube.

3. Tighten the pipe cover, mark it, put it in a plastic bag and seal it.

4. Send the samples for examination in time.

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

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

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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

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

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.

 

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

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

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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）

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

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

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

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

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

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

Comparison of advantages of various testing methods of COVID-19

Comparison of advantages of various testing methods of COVID-19

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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

Sample collection, oropharyngeal swab or nasopharyngeal swab

NAT Detection process Nucleic Acid Testing

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

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.

About us

Cell medical (Dongguan) Co., Ltd., a professional VTM kits and swabs manufacturer, has many years of experience in medical application molding and flocked treatment heads and swabs.

Our flocked swabs are famous for their stable and reliable performance and excellent absorption and elution ability.Certificate:FDA,CE,EU,Free Sale,Export license based on (GMP).

We 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.

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