How troublesome is nucleic acid testing? I feel embarrassed to ask for the results after reading this.

Many people think

Nucleic acid testing is just like blood routine testing.

Take specimens

▽

Put it on the instrument for testing

▽

Results soon

But the result is that——

what is going on?

Professionals finally gave the answer——

Real nucleic acid testing

It’s not as easy as you think!

01

Take samples at designated locations

Generally, nucleic acid sampling is carried out at designated locations.

02

Send the specimens to

Specific laboratory tests

Generally, the sampling point and the testing point are not together, so it is impossible to collect one and send one at a time, so there is a little delay here.

Then some people say, can’t the test be carried out right at the sampling point?

Of course not!

Nucleic acid testing is an extremely sensitive and precise experiment. Nucleic acid testing laboratories have special environmental requirements and cannot be carried out in any random place.

This is also the reason why we need to establish special modular laboratories to conduct nucleic acid testing.

03

After receiving the specimen

Disassemble the input system one by one

The specimens are escorted to the laboratory under strict packaging and must be signed for and entered into the information system.

This step requires unpacking one by one, and the double-layer sealed packaging, not to mention thousands of packages, can take a day to unpack...

Each one must also be sprayed with alcohol to ensure biosafety protection.

With a "beep" sound, the specimen information will be entered into the system and connected to the health code.

During this period, everything was done manually, which was not much faster than sampling.

Especially when dealing with massive amounts of specimens, we must ensure that there are no errors and that we do not mix up the information or find out at the end that something is missing or the number does not match and have to look for it again.

After all, it concerns everyone's health, and carelessness is absolutely not allowed.

04

Extraction of nucleic acids

Detecting viruses like "planting peanuts"

Can't the specimen be tested directly once it arrives at the laboratory?

No!

The specimen also needs to be pre-processed to extract the nucleic acid in the specimen before amplification can be performed.

Then the question arises again, what is amplification?

If the nucleic acid extracted from the specimen is regarded as a piece of land and the new coronavirus is likened to peanuts, how do we know whether there are peanuts among the many elements that make up the land?

Then just add some fertilizer and water and let the peanuts grow. One becomes two, two becomes four, four becomes eight...it's easy to find out this way.

Similarly, viruses are invisible, and trace amounts of samples are not easy to detect, so they must be increased in quantity to make them easier to detect.

During this process, medical staff still have to unscrew the lids one by one and use a sample gun to draw samples for nucleic acid extraction.

Sitting in front of a biosafety cabinet, I unscrewed thousands of lids, poked thousands of gun tips to absorb thousands of specimens, then knocked off thousands of gun tips and screwed on thousands of lids....

For them, this step can be said to be very sour~

05

In a completely pollution-free environment

Preparation of reagents

This step is completely pollution-free and requires strict and precise operation.

As many samples as needed, as many reagents and EP test tubes as needed, and thousands of gun tips as needed.

Moreover, it is all manually packaged and well protected to avoid contamination.

If you drop some "peanut seeds", you will get an incorrect result:

There were no peanuts in the soil, but a bunch of peanuts grew out of it. After all, the power of exponential multiplication is terrifying.

06

Sample addition should be fast, accurate and stable

And there must be 0 mistakes!

This step is still completely manual, and medical staff need to concentrate on the whole process.

Ensure 0 mistakes!

Moreover, the extracted nucleic acid is easily contaminated and easily degraded, so the operation must be absolutely cautious! After all, there may be dozens of specimens on a plate!

At the same time, only 5ul of the extracted nucleic acid needs to be added into the reagent system for amplification.

What is the concept of 5ul?

One tenth of a drop of water, with a tiny gun tip, you can only see that little bit on the top ~ and the operation process is required: fast! Steady! Accurate!

07

On-machine testing

Once you start, you can't stop

This process takes 1-2 hours, and once the instrument starts the amplification program, it cannot stop to add new samples. It is necessary to wait until the results of this batch of amplification are completed before the next batch of samples can be amplified.

Therefore, this is one of the reasons why nucleic acid testing cannot be carried out on a first-come, first-served basis, because once the instrument is turned on, it cannot be stopped and the current batch must be completed before the next batch can be carried out.

If we really want to test whenever we want, we need to do as Archimedes said:

"Give me a long enough rod and a fulcrum, and I can move the earth."

You can also say that

If you give me enough people, enough instruments, equipment and venues, I can test the new coronavirus nucleic acid samples as soon as they arrive.

But is all of this enough?

Definitely not!

When conducting each test, it is necessary to add various corresponding negative controls, positive controls, quality controls, and saline controls to monitor the quality of the entire experimental process and ensure the reliability and accuracy of the test results.

After all, there are too many steps in the experimental process and too many potential interference factors, so such measures need to be taken for each batch to ensure the quality of detection.

After the results come out, you still need to check the results, verify the specimen information, issue the results, and transmit the data (that is, issue the green code).

What are testers most afraid of?

Amplification failed.

Even though we have been very careful, it is difficult to guarantee perfect results every time.

Then, you know ~ review the process, analyze the problem, find the steps that may be affected, and do it again ~

When the instrument is running

Can the testers take some time off?

It’s such a beautiful thought!

When the instrument is running, a new batch of specimens arrives, and we have to start recording information, extracting nucleic acids, and adding samples again...

I can't stop at all!

There is a lot of preparation work involved:

Inserting gun tips (2 per specimen, thousands of specimens ≈ 10,000 gun tips, you do the math, there are only 96 gun tips in a box~), preparing consumables, maintaining equipment, environmental monitoring, cleaning up massive amounts of garbage, laboratory UV, and in addition, you have to go to the toilet at least once a day...

Don't worry, for your green code

Everyone is working hard

However, despite the complicated process and many influencing factors, please rest assured that the medical staff have undergone rigorous theoretical operation training and assessment, and are all certified~

Although it is difficult to test on arrival and get results as quickly as blood or urine routine tests, they are also working non-stop to get the results strictly within the specified time.

In the face of the epidemic, all staff have cancelled their rest breaks and fully supported nucleic acid testing to shorten the time for obtaining results. Your anxiety is also their top priority.

In this way, day after day, everyone worked together to ensure that batches of nucleic acid test results were issued on time under super logical arrangements.

In the face of the epidemic, every citizen has a responsibility.

We have seen that many people with lofty ideals are silently contributing their efforts to fight the epidemic, whether they are sample collectors and epidemic investigation personnel who rush to the front line, or inspectors who silently carry out tests behind the scenes; whether they are volunteers from various regions, or staff from various streets and communities; whether they are police officers, or every ordinary citizen who actively cooperates and responds to the government's call, let us join hands to fight the epidemic and overcome the difficulties together!

Source: Shenzhen Health Commission

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