The Real Time Reverse Transcription–Polymerase Chain (RT-PCR) test has fast-become the most sought after indicator of the presence of COVID-19 infection in an individuals body. It includes the extraction of ribonucleic acid (RNA), a genetic material of the virus, through the collection of specimen in the form of a swab, from a person suspected with COVID-19, or one experiencing symptoms.
However, in the recent times—amid the deadly second wave of the virus—there has been a spike in 'false negative' test reports, which has become a grave cause of concern for medical professionals, as well as the citizens of the country. With an increasing number of people testing negative on the RT-PCR test, despite exhibiting one or more coronavirus-related symptoms, doubts regarding the accuracy of the test are being raised.
If you happen to be (or know of) someone who is repeatedly testing negative on the RT-PCR, and continues to experience covid-related symptoms, here's what you should know!
According to Dr Arvind Malik, M.S, Deputy CMO, CHC Chaprauli, the accuracy of the RT-PCR test is limited based on the sampling sites and methods used, along with the need to test as soon as possible, in order to detect the virus. To avoid the possibility of a missed infection and widespread transmission of the virus, specimen samples for RT-PCR testing must be taken with first symptom onset. "Testing at a later date (as late as the 4th day of symptoms) will result in a higher probability of 'false negative reports' in people with SARS-CoV-2, particularly at upper respiratory sampling sites. After 10 days, it may be important to use lower RT or faecal sampling to detect the presence of an infection," he informs.
"Unfortunately, India lacks infrastructure sequencing. Hence, one is uncertain of the different types of mutant strains which are entering the local virus. Besides, these mutant strains have the capacity to mask themselves from the RT-PCR test, and aren't neutralised by the antibodies present in the body, explains Dr Charu Dutt Arora, Chief Intensivist and Covid Care Expert, Housepital, Sarvodaya Healthcare. As the mutated virus is escaping detection in the RT-PCR test, those experiencing symptoms are encouraged to get their CT scan done as well.
"While a virus can escape antibodies or mask itself in the cycle of RT-PCR, it cannot hide its presence inside the lungs. Which is why, if an individual has a strong presence of coronavirus or viral pneumonitis—as seen in the CT Scan, in the form of ground-glass opacification or sun plural patches—it can confirm COVID-19 in the body," she adds.