NEW DELHI: Test results may come out negative even if one has contracted Covid-19, experts have warned, advising that those showing symptoms of the disease must be treated without waiting for a confirmatory test to prevent aggravation of the infection.
There have been several cases where patients showing clinical symptoms of Covid-19 have reported false negatives multiple times. They were confirmed positive after repeated tests, doctors said.
The general perception of the experts now is that a high degree of suspicion arising out of the clinical symptomatology and the CT scan reports should be the guiding factor for treatment rather than relying only on the RT-PCR test which has a sensitivity of only 70 per cent, Dr Neeraj Gupta, professor in the Department of Pulmonary, Critical Care and Sleep Medicine at the Safdarjung Hospital, said.
Even the rapid antigen test has a sensitivity of 40 per cent. “So many patients will be missed if we rely only upon these tests,” Dr Gupta said.
The antibody tests have a sensitivity of 90 per cent but they are only useful for confirming past exposure for SARS-CoV-2 and have no value in the early stages of the disease.
“All the treatment strategies should be guided towards preventing the progress of the disease from its mild to moderate or moderate to severe and for that we cannot wait on test reports. We have to go by clinical symptoms,” he explained.
Dr Vijay Gurjar, an assistant professor in the department of Geriatric Medicine at AIIMS, New Delhi said that there have been several instances where the patients tested negative even after three or four RT-PCR tests despite clinical presentations and CT scans indicating atypical pneumonia which is highly suggestive of Covid-19. Later on, they were found to have antibodies against coronavirus which means they had the infection but their results had come out negative in the RT-PCR tests, he said “If patients have the symptoms, more so, if he or she is an elderly or has co-morbidities, they should be treated on the lines of Covid-19 and managed accordingly without waiting for the test confirmation,” Dr Gurjar said.
Tests not accurate
Experts feel that a high degree of suspicion arising out of the clinical symptomatology and the CT scan reports should be the guiding factor for treatment rather than relying only on the RT-PCR test which has a sensitivity of only 70 per cent.