What is PCR?

What is PCR?

All of us have heard the term PCR being used in some way or another. But many persons do not understand or know what PCR means? So in today’s post, we will break PCR down into simpler terms for you.

 What is PCR?

PCR, which is short for Polymerase Chain Reaction, is a method used by scientists to create numerous copies of a particular section of DNA. The process is fast and typically delivers accurate results. The polymerase chain reaction is used in research to make a massive batch of DNA samples that researchers can use for several experiments and investigations. Usually, they utilize it for studies of forensic analysis, medical diagnosis, molecular biology, and evolutionary biology.


Before the PCR method was invented, scientists would use a very tedious process to copy DNA. However, In 1983, an American biochemist named Kary B. Mullis developed the Polymerase Chain Reaction method, which now generates DNA copies in just a couple of hours. Now, the PCR test is used as a common tool to identify the presence or absence of a gene. This helps identify pathogens (disease-causing organisms) during an infection.


In essence, the PCR test is used primarily for persons being tested for COVID-19. This virus has ravaged the world in multiple forms, creating needs in many countries, one of which is PCR testing. In fact, on May 20, 2021, UNICEF made a desperate plea for assistance for Southern Asia, where they needed US$40 million for medical and diagnostic equipment, including those for PCR testing. Further, in an article published by the US National Library of Medicine National Institutes of Health, it was reported that the UK and USA have opened drive-through testing centers for PCR testing. Additionally, as of March 7, 2021, 363,825,123 have been PCR tested in the United States.


How is a PCR Done?

Using the PCR method involves inserting a swab into the nostril, and while it may prove uncomfortable, it should be painless. In the UK, self-testing is allowed. As such, the NHS provides a detailed description of the PCR testing process on its website. It involves:

  • Cleaning your hands
  • Place items from the test kit onto a clean surface
  • Blow your nose and wash your hands again
  • Open your mouth wide and rub the swab over your tonsils
  • Put the same swab inside your nose
  • Put the swab facing down into the tube and screw the lid tight
  • Put the tube in the bag provided


If you get this test done by a professional, they would use the same or pretty similar steps. After sample collection is the extraction phase. At this point, the sample arrives at the lab, and the technician will proceed to isolate DNA material from the sample. They will then use chemical compounds and a thermal cycler (PCR machine) to generate a reaction and make millions of copies of a small section of the coronavirus’s DNA for further testing. If the virus is present, one of the chemicals shows a fluorescent light.


We hope you now have a clearer understanding of what a PCR test is, and we look forward to having you read our next post. Till then, keep safe.


PCR Test for COVID-19: What it Is, How its Done, What the Results Mean. (2020). Cleveland Clinic. https://my.clevelandclinic.org/health/diagnostics/21462-covid-19-and-pcr-testing

 ‌NHS Choices. (2021). How to do a PCR test. https://www.nhs.uk/conditions/coronavirus-covid-19/testing/how-to-do-a-test-at-home-or-at-a-test-site/how-to-do-a-pcr-test/

 ‌polymerase chain reaction | Definition & Steps | Britannica. (2021). In Encyclopædia Britannica. https://www.britannica.com/science/polymerase-chain-reaction

 ‌Burki, T. K. (2020). Testing for COVID-19. The Lancet Respiratory Medicine, 8(7), e63–e64. https://doi.org/10.1016/s2213-2600(20)30247-2

 The COVID Tracking Project‌. (2021).Totals for the US. https://covidtracking.com/data/national

 ‌As deadly surge of COVID-19 sweeps across South Asia, UNICEF calls for US$164 million to help save lives. (2021). Unicef.org. https://www.unicef.org/press-releases/deadly-surge-covid-19-sweeps-across-south-asia-unicef-calls-us164-million-help-save

‌What is PCR (polymerase chain reaction)? (2015, September 11). @Yourgenome. https://www.yourgenome.org/facts/what-is-pcr-polymerase-chain-reaction


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  • Cecilia Arias
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