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RT-PCR:

Topics Covered : Issues related to Health.

RT-PCR:


Context:

As per the latest order of the Karnataka Government, passengers arriving from any State to Bengaluru must possess a RT-PCR negative report.

How RT-PCR is used for detecting Covid-19?

  • The causative agent for Covid19 is the SARS-CoV-2 virus. It is an RNA virus, that means it infiltrates a healthy cell to multiply and survive.
  • Thus, the RT-PCR test is for the identification of SARS-CoV-2 RNA. In this, the RNA is converted to DNA through a process called ‘reverse transcription’ for detecting viruses.

How it is carried out?

  • The SARS-CoV-2 RNA is generally detectable in respiratory specimens during the acute phase of infection.
  • For that upper and lower respiratory specimens (such as nasal, nasopharyngeal) are collected.
  • This sample is treated with several chemical solutions that remove substances, such as proteins and fats, and extracts only the RNA present in the sample.
  • Real-time RT-PCR setup usually goes through 35 cycles, which means that by the end of the process, around 35 billion new copies of the sections of viral DNA are created from each strand of the virus present in the sample.
  • As new copies of the viral DNA sections are built, the marker labels attach to the DNA strands and then release a fluorescent dye, which is measured by the machine’s computer and presented in real-time on the screen. The computer tracks the amount of fluorescence in the sample after each cycle. When the amount goes over a certain level of fluorescence, this confirms that the virus is present.

InstaLinks:

Prelims Link:

  1. Difference between RNA and DNA.
  2. Differences between RT PCR and antibody tests.
  3. What is a RNA virus? How it survives?
  4. What are antibodies?

Mains Link:

Discuss the significance of RT- PCR test.

Sources: the Hindu.