When I was a child
Nostalgia was a small stamp
When I grew up
Nostalgia was a nucleic acid test report that said “negative”< /p>
(Image source: Internet)
Our lives are shrouded in the shadow of the epidemic again
When going out, it is as important as the ID card——
There is also a negative nucleic acid test report
Are you curious:
From your arrival Nucleic acid testing site
then-
raise your head
put the swab down your throat & nostrils
(Picture source: Internet)
What happened in the more than ten hours to get the nucleic acid test report?
What happened to your throat/nasal swab that was taken? How did your nucleic acid report come about?
Today, we come to the most complete reveal.
Everything starts long before you go downstairs to check.
First of all, in the selection of the temporary sampling room, the following series of work have been done to ensure safety and accuracy. It is not as simple as “setting a stall” on the roadside.
Next, is sampling.
For you, all you need is
“Open your mouth—”
“Tilt your head up a little—”
Why A cotton swab is either a nostril or a throat?
The nasal cavity and throat are the only way for excretion of respiratory secretions, so the presence of the new coronavirus can be found here most.
The new coronavirus pneumonia virus is transmitted through droplets or aerosols, mainly infecting the respiratory system of the host. The virus colonizes the respiratory tract and reproduces rapidly. The number of viruses increases sharply and is excreted through respiratory secretions.
Poke the nose to detect the nasopharynx, and poke the throat to detect the oropharynx. Their positions are relatively deep, and there is essentially no difference.
In order to ensure accurate sampling, laboratory personnel need to ensure the standardization of specimen collection.
Whether it is a nasopharyngeal swab or an oropharyngeal swab, there are certain requirements for the depth of collection.
So, when you rant about being stabbed in the throat so badly that you get calluses in your throat—
( Image source: Internet)
It’s not that the staff has a grudge against you.
If it is nasopharyngeal swab sampling, the key points of sampling are: “to be deep, to transfer, to take cells.”[2]
“to be deep” means to go deep from the earlobe Part to half the length of the tip of the nose
“to turn” means to turn 10~15s, about 4~5 turns
“to take cells” means to take the cells of the nasopharynx
p>
(Image source: Reference [2])
If it is an oropharyngeal swab, it is also necessary to use Swab the bilateral pharyngeal tonsils and posterior pharyngeal wall 3 to 5 times.
After clearing the sample, the staff will immerse the swab tip into a tube containing 3ml of virus preservation solution (isotonic saline solution, tissue culture solution, cell preservation solution or phosphate buffered saline can also be used) , the tail is discarded, and the cap [2] is tightened.
Just like that, your throat/nasal swab sample will be stored in an airtight container.
The new coronavirus is highly contagious, so the nucleic acid testing staff should also be fully armed to ensure safety.
When collecting samples and before entering the laboratory, be sure to use secondary protection before entering, that is, wear disposable protective clothing, goggles or face shields, double gloves, N95 or above masks, and hats And protective boot covers, etc., so the staff you see doing nucleic acid testing are mostly fully armed.
The heavy protection isolates the virus, but it is also heavy. Even “cold in winter and hot in summer”. Therefore, when testing in cold and hot places, the staff will need more strong intentions.Chi. (Thank you for your hard work!)
(Image source: Chinese government website. August 4, 2021 , at the Shuanghe Road Community Sampling Point, Shuangfu Street, Jiangjin District, Chongqing City, Zhao Qingyong, a medical staff member of the Third People’s Hospital of Jiangjin District, completed two rounds of sampling work, took off his protective clothing and went upstairs [3].)
Staff wearing secondary protective equipment will also spray the outside of the sealed bag with 75% alcohol or disinfectant containing effective chlorine to prevent the surface of the test tube from carrying viruses, and then store it in a dedicated sample The transfer box, after being packed in layers, will be transported to the testing laboratory by a special person and a special vehicle.
Testing does not begin immediately after a sample is escorted to the laboratory. The staff will open the packages one by one and enter the information of each specimen into the system, just like giving each specimen an account.
After entering, each sample has its own unique identity on the Internet, and then its test results will be firmly bound to your health code.
Finally, the critical sample processing and detection stage has come.
You may have had this question: How do scientists know whether there is a virus in your body?
To answer this question, we must first understand a professional detection technology – nucleic acid amplification technology, which can detect the presence of specific gene fragments in the sample. At present, the kits that have been approved for marketing in my country are also based on nucleic acid amplification technology.
If you haven’t returned all your high school knowledge to the teacher, you may remember it.
Every sample must be tested for the nucleic acid of the new coronavirus, and the nucleic acid must first be extracted, which is commonly referred to as a template. After the template and detection reagents are mixed in a certain ratio, they can be tested on the machine.
In the reaction tube, the primers contained in the reagent will bind to the specific gene sequence of the new coronavirus nucleic acid, and continuously copy new nucleic acid fragments under the action of enzymes. Each round of the reaction results in a single copy of a specific nucleic acid fragment, multiplying the number. Each time a specific gene is copied, a fluorescent signal is released.
If a specific gene segment does exist in a sample, it will emit a specific fluorescent signal.
At present, the loci targeted by the nucleic acid detection of 2019-nCoV mainly include 3 conserved gene sequences in the viral genome, namely the open reading frame 1ab (ORF1ab), the nucleocapsid protein (N) gene and the envelope The protein (E) gene was used as the detection target.
If there is no significant change in the fluorescence signal, then congratulations – the probability is safe [4].
(Image source: Reference [4])
But not necessarily.
This is because the nucleic acid test of the new coronavirus has the possibility of false negatives. Negative results cannot rule out new coronavirus infection, and the reasons for false negatives in each link should be considered.
The currently used nasopharyngeal swabs or throat swabs are mainly tested by qPCR kits, which only have a positive detection rate of 30% to 50%. In order to ensure the rapid screening of large-scale personnel, under the current technology, such false-negative results cannot be avoided, so in epidemic areas, quarantined personnel often need to undergo nucleic acid testing multiple times [2].
That’s seven or eight times in the throat/nose a day. (You are working hard)
A negative test result does not necessarily mean that there is no infection; and if the test result is positive, then you will be nervous.
At the time of mixed test, it can only be judged that there may be positive specimens in this batch of samples, then another nasal/pharyngeal swab-nucleic acid test will be carried out for the people who are mixed with the test to determine the positive infection Who exactly is.
In order to prevent possible contamination, the tested samples will also be put into designated medical trash cans for high-pressure destruction.
Congratulations, it’s overcast.
Finally, the finishing touches come.
The staff will check the information one by one and upload the test results to the system. It is this step that allows you to easily find the results on the Internet.
“Negative” – would be the two most pleasant words.
(Image source: Internet)
However, it should be noted that the new coronavirus will continue to be in the human body. Alternate states, which cannot be detected if sampled during the suppression period.
If you drink water, smoke, or drink alcohol before sampling, it may also interfere with the test results.
So, even if the result is negative, everyone should go out all the timeWearing a mask is responsible for yourself and others!
(Image source: Internet)< /p>
Recently, many people are sighing with emotion. I didn’t expect that it has been more than 2 years, and the epidemic is still affecting our lives.
Protecting ourselves at all times, actively vaccinating (remember to do it if you haven’t received a booster shot), and continuously improving our anti-virus ability is the correct solution.