What is the RT-PCR Test?
PCR is used widely for carrying out molecular-based diagnostic tests. It is used to detect viruses responsible for diseases such as HIV, Ebola, African swine fever, foot-and-mouth disease etc RT-PCR test, and antigen tests (Serology) are two different types of tests carried out for the diagnosis of COVID-19. The Real-Time RT–PCR is suitable to detect the COVID-19 virus as it contains only Ribonucleic Acid. The full form of RT-PCR is Reverse Transcriptase Polymerase Chain Reaction. It is the most sensitive technique for mRNA detection. It quantifies the presence of a particular genetic material of the virus or any pathogen.
Real-Time RT-PCR is loaded with fluorescent dyes as markers. Real-Time RT-PCR helps investigators, mainly scientists or virologists, to analyse the results without delay. RT-PCR test detects the COVID-19 virus after a nasopharyngeal swab is collected from a patient. It detects the virus even if the viral load is less. The major advantage of Real-Time RT-PCR is that it gives rapid results.
What is the procedure for RT-PCR Test for the COVID-19 virus?
The following are the RT-PCR Test procedures (guidelines) in brief that are helpful in the diagnosis of COVID-19.
Step 1:- The COVID-19 virus generally gathers in the throat or inside the nose of a person. The RT-PCR Test diagnosis process starts with sample collection by swab from the mentioned body parts.
Step 2:- The cells and nucleus are lysed by treating them with different chemical solutions. Finally, the sample only contains DNA and RNA. It is a combination of the residual genetic material of the individual and the RNA of the virus.
Step 3:- The RNA is then converted to DNA using a specific enzyme via reverse transcription. Short fragments of DNA are also added to create a mixture.
Step 4:- If there is a virus in the sample, then the short fragments of the DNA accord to the target divisions of the viral DNA.
Step 5:- The mixture is then put into an RT–PCR machine. The RT-PCR machine heats and cools the mixture by cycling it through temperatures to ignite specific chemical reactions. Through this process, the target sections of viral DNA get their new identical copies.
Step 6:- The RT-PCR COVID-19 Test machine carries out repeated cycles with the sample. This helps in copying the target sections of the viral DNA. At the end of each cycle, the number of copies of the viral DNA gets doubled. As a result, about 35 billion new copies of the viral DNA sections from each strand of the virus are generated by the end of the process.
The RT-PCR testing time is only 5-10 minutes, but the entire procedure takes up4 to 8 hours.
How is the result concluded?
Once the new copies of the viral DNA are formed, the marker labels then attach to the DNA strands. The RT-PCR machine is connected to a computer that records the amount of fluorescent dye released after each step. It displays the result on the screen at the same time. At a certain point, when the amount of fluorescence crosses a particular limit, this confirms the presence of the virus. A very interesting fact to know is that the fewer the cycles to confirm the virus, the more severe is the condition. The RT-PCR test result can be either positive or negative. The test cannot predict when and how the virus infected you. A positive RT-PCR test means that you are likely to be infected with COVID-19 virus.
RT-PCR test report time can take 4 to 8 hours. One should take proper care of themselves as per the guidance of the physician to prevent the spreading of the virus. You can request to get an RT-PCR test online report on your mail.
How much is the cost of the RT-PCR Test?
RT-PCR COVID-Test technique is widely used because it is reliable. The test can give the result as early as four hours. However, laboratories generally take around four to eight hours to give the report. The Indian Council of Medical Research had earlier quoted Rs.4,500 as the cost of PCR-Test for private laboratories in India, same as the pathology lab. At present, the price of an RT-PCR test to detect COVID-19 is somewhere between Rs. 2,200 and Rs.3,000 in India. RT-PCR test is necessary to determine the individuals infected with COVID-19 so that proper management of the patients can be done. This will bring down the death rate.
Agilus Diagnostics, a subsidiary of Fortis Healthcare Limited
