What is PCR Testing – How does PCR Testing Work? – COVID19

What is PCR Testing – Every day, we learn something new. Sometimes it is associated with our professional lives, or sometimes it is associated with our personal lives. You can become a master in a field and learn everything regarding that, but there is a probability that you might even know the basics of other professions and industries.

When COVID started spreading in the world, including the United States of America, we learned something called PCR. The Centers for Disease Control and Prevention starters suggest everyone get themselves tested with the PCR COVID test to ensure their safety along with the safety of their friends and family.

After that, the Food and Drug Administration of the United States gave its approval to a rapid antigen test which was faster but less accurate. A lot of enthusiasts started questioning what PCR testing is. As it is associated with medical professionals, we cannot blame having the basic knowledge regarding PCR testing. Keeping that in mind, today we are here going to discuss everything related to PCR testing. So let’s get started. 

What is a PCR test?

Let’s start with the basics. PCR stands for a polymerase chain reaction. It is sometimes also called molecular photocopying, which is a fast and inexpensive technique used to amplify small fragments of DNA.

PCR testing, or polymerase chain reaction testing, was developed by doctor Kary back in 1983. PCR was a revolutionary technology as high amounts of DNA are necessary for molecular and genetic testing.

On the other hand, PCR technology allows scientists to generate millions of copies from a very small amount of DNA to test it. For example, PCR testing became very famous during the spread of COVID-19 in the world.

Types of PCR Testing.

Before we move ahead, let’s first discuss the types of PCR testing. Yes, there are several different types of PCR testing as it is not just limited to nasal swabs. Different tests can detect the disease differently.

  • A nasal swab test is among the most common types of PCR tests. It involves a swab taking a sample from the back of your nose and throat.
  • The second most popular PCR test is the saliva PCR test. Your health care expert or sample collector will ask you to spit your saliva into a tube, and later they are going to use that tube as your sample.
  • The next type of blood test is the PCR test which requires the blood sample to be collected through your vein. It is not a very popular test when it comes to testing any flu or virus.
  •  The last type of PCR test is a nasal mid turbinate swab. It is also similar to a nasal swab, but this time, a health care provider or sample collector is going to use the swab and take a sample deep inside the nostrils.

What are the Uses of PCR Testing?

Polymerase Chain Reaction (PCR) Testing is used in a huge number of diseases. It became one of the most famous and accurate tests during the spread of COVID-19 in the United States and all around the world.

You might be surprised to know that scientists did not develop PCR tests just for COVID-19 as it has been used since 1983. It is among the most effective tests for detecting several viruses and viruses.

  • Influenza
  • tuberculosis
  • HIV
  • Ebola
  • Hepatitis C

Apart from these diseases, health experts can also detect small amounts of cancer and genetic changes using PCR tests. 

How does PCR Testing Work?

Once you have understood how health experts use PCR testing, it is time for you to learn about how PCR testing works. It will give you insights into the working of PCR tests in reality.

Sample collection

The first step in PCR testing is the collection of samples. A health expert or healthcare provider will use a swab to collect samples from the respiratory tract of the patient. 

A swab is a long flexible stick that has a soft tip that goes directly into your nose. The health expert over the sample collector is going to insert the swab for two to three inches into your nose to collect the sample.

Once the sample has been taken by the health care provider, they will seal the swab in an airtight tube and send it to a nearby laboratory.

Your doctor or health care provider can also take a sample using your blood or issue four PCR tests as it is not just limited to saliva or mucus. It all depends on the type of disease. 

If you don’t know how to take a sample, then you can take a look at the below given how to take a nasal slab sample in PCR testing.

laboratory process

Once a sample has been taken by the health expert, it will be sent to a nearby laboratory where the leper tree experts are going to do the rest of the work and come up with the results.

A laboratory researcher is going to use a special machine to heat the sample, which is going to separate the DNA inside into two pieces of single-stranded DNA. After that, it is going to cool down and allow the primers to attach to the template DNA sequence. This process is going to create the duplicate DNA of the original sample.

Later, the machine is going to repeat the whole process as many times as necessary to create the required copies to perform the test.

For example, viruses like COVID-19 contain RNA rather than DNA. RNA is a little bit different, and the machine has to go through a different process called reverse transcription PCR, also known as the RT PCR test.

What is PCR Testing
What is PCR Testing


The final step of PCR testing is providing the results of the test. The result is not going to be equal in the whole world as it can vary from a few minutes to several days.

Apart from that, on-site analyzers and off-site analyzers can also create a huge difference in the timing of results. With the onset analyzer, health experts can provide results at a rapid pace. On the other hand, the result is going to take much longer if it has to go to a nearby laboratory.

Researchers are highly accurate as health experts, and systematic reviews found that PCR tests are as accurate as 97.2% in detecting COVID. On the other hand, rapid antigen tests are as accurate as 80%.

How to take a nasal swab sample in PCR Testing?

Nasal swab type of PCR testing is among the most common types of PCR testing in the world. A health care expert will take a soft pointed flexible stick and insert it through your nostrils. Usually, health experts insert two to three inches of the swab into your nose.

  • To take the end user swap PCR test take a soft pointed flexible swab and gently insert the swab inside the nostril of the patient.
  • Once the swab is 2 inches inside the nose, kindly rotate the swab and leave it in place for around 5 to 10 seconds.
  • After that, remove the swab from the nose and insert it into the second nostril.
  • Use the same rotating and leaving technique once again in the second nostril.
  • After that, you can remove the swab and insert it into an airtight pack.

Is there any risk of a PCR Test?

PCR testing usually does not impose any risk at all, but sometimes it can be a little dangerous. As you already know, there are different types of PCR tests, and the adverse effects are going to depend on the type of test you are taking.

For example, people who are taking a blood PCR test might experience slight pain or bruise after giving the blood sample. Usually, people start feeling better from that pain or bruising after a few hours.

On the other hand, a swab test from the nose or throat may cause mild cough or discomfort. Apart from that, there is also a probability that you might experience a light gagging sensation after taking a nose swab PCR test.

All of the above-given adverse effects, depending on the type of tests, are going to be temporary, and the affected person will start feeling better within a few minutes to hours.

Which type of test is better? PCR testing or antigen testing?

Both types of tests are good and capable of easily detecting COVID-19. PCR test and antigen test are both molecular tests that can detect a current infection. The antigen test is going to detect the presence of viral proteins, not viral RNA. It is also known as the lateral flow test. This type of test is usually cheaper and faster in providing results as compared to PCR tests. Antigen tests are less accurate as compared to PCR tests. It all depends on how you are going to use the test.