Flimsy testing for coronavirus is ‘like flipping a coin’
BHARGAVA: AROUND 25-30 PER CENT OF THE COUNTRY’S DAILY TESTS NOW ARE RAPID ANTIGEN
India’s bid to control its surging virus infections by increasing the use of fast but less sensitive tests could actually be making things worse for the South Asian nation.
With one of the world’s fastest-growing epidemics but also one of the lowest testing rates, India in late June started to use quick antigen tests to ramp up detection. But the tests, which can report false negatives as much 50 per cent of the time, threaten to obscure the true picture of its outbreak, further challenging containment efforts.
Between 25-30 per cent of the country’s daily tests now are rapid antigen tests, Balram Bhargava, the director general of the Indian Council of Medical Research, told reporters at a briefing in New Delhi. It was the first time India’s premier research group had broken down the testing data — the ICMR’s website still does not specify what type of tests are being done in its daily data. In some cities, the rapid testing numbers are even higher — the latest data as of August 12 showed New Delhi conducted 12,422 rapid antigen tests and 6,472 of the more sensitive real time-polymerase chain reaction tests.
India’s practice of conflating the data from rapid tests and traditional RT-PCR ones risks obscuring its true infection picture
RT-PCR tests
The reliance on these tests casts further doubt on the ability of Indian government to stem the epidemic, which is now surging unchecked through the nation’s hinterland. It may also mean the falling case numbers seen in its big cities could be due to false negatives, raising questions over whether infection is truly being curbed. Worse, the use of rapid tests could be letting some infected people return freely to the community.
Most other countries with big outbreaks like the UK and the US use the RT-PCR tests that detect the genetic material of the virus.
While experts say that rapid antigen tests can help countries with out-of-control outbreaks quickly detect where hot spots are, India’s practice of conflating the data from rapid tests and traditional RT-PCR ones risks obscuring its true infection picture.
“If the rapid antigen tests are only 50 per cent sensitive compared to PCR tests and there is a very high prevalence of community transmission then they are not very good test,” said Peter Collignon, a professor of clinical medicine at the Australian National University Medical School. “Flipping a coin might almost be as good.”