PCR is the most common word these days in the disease diagnostic section. Many people are looking at the count of positive PCR results to determine the current state of this COVID 19 pandemic. You may have heard the word of PCR. But do you really know how the PCR test working?? Let’s figure it out today.


Is PCR a test for diagnosing covid? The simple answer is “NO”. PCR is not a testing method that is designed to test covid 19. It is a molecular biological technique that is used to amplify the number of copies of a sample DNA region. Click here to know more about how PCR works.

 This technique is also used to diagnose diseases. It is one of the well-known methods of infection diagnostic which was using in the world long time before covid comes. There are four main types of testing methods for diagnosing viral or bacterial infections. To know more click here to the article about viral/bacterial testing.

Let’s talk about PCR in here.

PCR which stands for Polymerase Chain Reaction, is a gold standard method for identifying viral or bacterial diseases. The name “gold standard” is used for this test because it gives highly accurate results in a very short period of time. In simple, checking about the availability of infectious molecule’s DNA is done here.

Let’s take Covid 19 as an example. Covid 19 is an RNA virus. But PCR method only works for DNA samples. Therefore, first, we have to turn viral RNA into DNA. This process is called reverse transcription. For an extra fact, the actual testing method for coronavirus is “rRTPCR”. Which stands for “reverse transcriptase Real-Time PCR”. With the use of the term “real-time”, you will find why at the end of this article. After turning the viral RNA into DNA, those DNA samples is going through the PCR process. It is a series of reactions. Click here to know about the process detailed.


After the reaction process completes, the sample is separated using the technique called “Electrophoresis”. Earlier, technicians had to wait until the electrophoresis completes to see the results of the test. But now with the latest technology, the availability of the sample DNA to the viral DNA can be seen in real-time using computer graphs. That’s why the test is now called a real-time PCR.

The PCR result actually comes as “Detected” or “Not-Detected”. The detection is considering a positive result. Sometimes they run tests for another time to be sure about the result.

Hope you guys got some idea about what actually PCR is. Share it with your friends and spread the knowledge!!

Feature image by National Cancer Institute on Unsplash

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