How is COVID-19 detected in the RT-PCR test?

Description of COVID-19 RT-PCR test: In 2^nd The wave of COVID-19 has swept the country, and the demand for RT-PCR testing, which can detect viruses early and support timely treatment of infected people, has become extremely important. Many people took the RT-PCR test last year, but people rarely know and understand the science behind it. What is the RT-PRC test? What does RT-PCR stand for and how accurately does the test for detecting COVID-19SARS-CoV-2 work? Decipher the science behind it.

What is an RT-PCR test?

Scientifically speaking, real-time RT-PCR is an innovative nuclear-derived test method that is widely used to detect the presence of specific genetic material in any pathogen, including viruses. In its early stages, it included a test method to detect genetic material using radioisotope markers. The use of radioisotopes was time consuming and cumbersome as test results were obtained only at the end of the process. However, over the years, technology has evolved further, replacing radioisotope markers with special markers. The special marker is most often a fluorescent dye, with almost immediate results even if the process is still in progress.

When it comes to testing for viruses, RT-PCR is considered to be one of the best methodologies available to us. Apart from the COVID-19 SARS-CoV-2 virus, this test is also widely used to test for other virus-based diseases such as Ebola and Zika virus.

What are viruses and their genetics?

Before understanding how the RT-PCR test works to detect the SARS-CoV-2 virus, we updated elementary-level biology to see what the virus really is and what its composition is. It’s time to know. The simplest definition for a virus is: “A virus is a microscopic package of genetic material surrounded by a molecular envelope. This genetic material is either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).”

Today, viruses are basically composed of protein shells that contain trace amounts of DNA or RNA genetic material. Viral manipulation methods include entering the host (human body), attaching to the host’s cells with the help of protein shells, and releasing and replicating genetic material into the cells. The replicated virus then infects other healthy cells in our body and makes us sick.

The last bit of biology lessons needed for our discussion is about RNA and DNA. DNA stands for deoxyribonucleic acid and is a two-stand molecule that carries the genetic code or blueprint for how these organisms are made and developed. In most cases, all organisms have a DNA molecule. RNA, on the other hand, is an abbreviation for ribonucleic acid (RNA), a single-strand molecule that copies and transcribes part of the genetic code and transmits it from proteins to the host body.

Because the SARS-CoV-2 virus is an RNA-based virus, it invades healthy cells and uses them to proliferate and survive. Once inside the cell, the virus uses its own genetic code (RNA in the case of the COVID-19 virus) to control and “reprogram” the cell, turning it into a virus factory.

What is Libyan transcription?

RT in the RT-PCR test stands for reverse transcription, and the SARS-CoV-2 virus is an RNA-based virus, so it is an important step in the testing process. To detect the presence of the COVID-19 virus in the human body, scientists need to convert RNA into DNA. This is a process called “reverse transcription”. Reverse transcription from RNA to DNA is performed because only DNA can be copied or amplified under laboratory conditions. This is important for the detection of COVID-19 virus.

To detect viruses in the human body, laboratories amplify certain parts of the transcribed viral DNA hundreds of thousands of times. This is to avoid having to look for small traces of viral RNA, but instead identifies large numbers of infected DNA stands, which helps in early detection of the virus.

How does the RT-PCR test detect the COVID-19 virus?

The RT-PCR test performed to detect the SARS-CoV-2 virus, or COVID-19 virus, involves the following steps:

• Sample collection: Samples are taken from the part of the body where the virus collects to test for the presence of the virus in the host / human body. In the case of SARS-CoV-2, it is the nose or throat of a person. Therefore, these samples are collected using a swab probe.
• Sample improvements.. In the second step, the collected sample is chemically treated and purified to remove other substances such as proteins and fats. This is done to ensure that the sample contains only RNA genetic material, which can be extracted for testing. This extracted RNA is a mixture of human genetic material and viral RNA, if any.
• Reverse transcription: As explained above, RNA cannot be amplified in the lab, so it is reverse transcribed into the form of DNA using certain enzymes. During this process, the lab also adds short fragments of DNA that are complementary to specific parts of the transcribed viral DNA. If the virus is present in a sample of the host body, it attaches to the target section of viral DNA.
• RT-PCR testing machine: Here, this sample is placed on an RT-PCR machine that basically undergoes several cycles of temperature fluctuations, heating and cooling of the sample, in order to trigger a specific chemical reaction. During this process, a new identical copy of the target section of viral DNA is created, doubling the presence of the identical copy with each new cycle. Typically, 35 cycles are performed for each RT-PCR test. This means about 35 billion new copies of the section of viral DNA by the end of the process.
• Detection by fluorescent dye: When a new copy of the viral DNA stand collects in the sample, the marker label attaches to the DNA strand and emits a fluorescent dye. The testing machine’s computer tracks the fluorescence level of the sample after each cycle and confirms the presence of the virus when a certain threshold is exceeded. The severity of the infection can be determined based on how many cycles it took for the machine to cross the set threshold.

PS: Some of the facts and scientific processes described above have been “oversimplified” to help the general public understand the highly complex scientific testing process. The intent is to develop a general understanding of the concept, rather than providing all the details in a very specific way.