New Delhi: Negative RT-PCR (Reverse transcription- Polymerase chain reaction) reports despite patients showing full-blown symptoms of COVID-19 have become a matter of concern amid the surge in the virus. People are perplexed by these false-negative reports. The speculation is that it is because of the new mutant strains.
Dr. Anurag Agarwal, Director of the National Institute of Biomedical Genomics confirmed that while it is possible that a COVID positive person may test negative in an RT-PCR test, it should not be attributed to the double mutant strain.
“Double mutant was sequenced through PCR positive. So it is not possible that the mutant escapes the RT-PCR test. Then we could not have sequenced it,” Dr. Agarwal said in a video, tweeted by the Union Health Ministry.
“All possible sequences in the world are being checked regularly and there is no strain which can escape the double gene testing,” he said.
People should remember is that PCR has a sensitivity of 70 per cent. “The load of the virus in one’s mouth and nose remains the highest a day before the symptoms start showing. Then the virus load gradually decreases. If people get tested late after 7 to 8 days, it is possible to get a negative test report because the virus may have travelled inside the body,” he said.
Tests coming negative despite symptoms being present is not new and not because of any new strain. This was the case since the beginning, that if delays testing, the test results may come negative, Dr. Agarwal said.
Double mutant is a new strain formed by two mutated strains. In India, its presence has been found in many states, including Maharashtra and Delhi. E484Q and L452R strains have formed the double mutant.
