Are RTCPR tests unable to detect new mutants? Here's what Dr Souradipta Chandra has to say

FPJ Web Desk | Updated on: Friday, April 23, 2021, 08:33 PM IST

Photo Credit: PTI
Photo Credit: PTI

As COVID-19 cases in India continue to rise, several changes have been observed. There are now several mutant strains of the virus in circulation across India, with many holding the Indian-origin double mutant strain responsible for the rapidly climbing caseload.

But even as concern over the double mutant strain strain B.1.617 SARS-CoV-2 prompts growing concern in India and abroad, there is now a third mutation to contend with.

Amid concerns over the new mutant spread in India, several have raised doubts on RTPCR detecting the mutant. Speaking about the same Dr Souradipta Chandra said, "New mutant seems to be undetectable by RTPCR test. I believe there are double & triple mutant varieties&due to change in structure, RTPCR tests unable to detect."

Dr Chandra is a Consultant Physician, Helvetia Medical Centre, Delhi and Principal Medical Advisor, European Union in India.

Adding that new varieties seem to cause new symptoms, he said that "We're seeing patients with diarrhoea, abdominal pain, rashes, conjunctivitis, confusion state, brain fog, bluish discolouration of fingers & toes, bleeding through nose & throat apart from usual symptoms -sore throat, body ache, fever, loss of smell and taste."

Meanwhile, Dr Anurag Agarwal, Director, Institute of Genomics and Integrated Biology, New Delhi said that If people with symptoms go for RT-PCR test late, after seven-eight days when symptoms become high, then there is a possibility of the test report coming negative.

Amid rumours that new mutants of COVID are behind the false-negative reports of RT-PCR tests of infected patients,he said, "These double mutants were sequenced only from the samples that had positive PCR reports. So there is no possibility that this mutant cannot be detected through the PCR test. Nothing can escape the double gene. People should know the PCR's sensitivity is 70 per cent."


"If people go for the test late, after seven-eight days when symptoms are high, there is a possibility of PCR (polymerase chain reaction) test coming negative but positive in CT (cycle threshold). This not about a new strain. It is the general behaviour of any virus. When people go for a test late, then many times PCR test comes negative in the nose and mouth. It is because the virus goes deeper inside the body," he explained.

The double mutant strain was found in saliva samples collected from Maharashtra, Punjab, and Delhi.

There is apprehension among experts that the new variant could also increase infection rates and easily surpass immune defences.

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Published on: Friday, April 23, 2021, 08:33 PM IST