Covid: Daily RT-PCR tests touch record 15,000-mark, cases above 3,000 in Delhi

The number of RT-PCR tests have been on the rise for nine days, with the last three days notching record numbers. The number of RT-PCR tests on an average have accounted for 23.6% of the total tests during the last seven days, data shows

The number of RT-PCR tests conducted in a day in Delhi crossed the 15,000 mark for the first time on Friday since the city began testing for the viral Covid-19 that first surfaced in March this year and has since infected 324,459 people. At least 5946 people have succumbed to the virus so far

Experts lauded the Delhi government’s efforts to ramp up RT-PCR tests while adding that there was still a lot left to be done. (Sonu Mehta/HT file photo)

On Friday, at least 15,660 tests using the more accurate molecular RT-PCR method was reported in the daily health bulletin released by the state government.

The number of RT-PCR tests have been on the rise for nine days, with the last three days notching record numbers. The number of RT-PCR tests on an average have accounted for 23.6% of the total tests during the last seven days, data shows. This is an increase over the average 19.8% recorded during the week before, and 19.03% in the week before that.

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The RT-PCR tests amplify the RNA of the Sars-CoV-2 virus to detect infection. It is very sensitive and less likely to give false negatives as compared to the alternate rapid antigen tests. The rapid antigen tests are cheap, easy to deploy in clinics and dispensaries, and can give the results within 15 minutes. However, the antigen tests are only 50 to 60% sensitive and can throw a lot of false negative results for people, who might actually have the infection.

Experts lauded the Delhi government’s efforts to ramp up RT-PCR tests while adding that there was still a lot left to be done.

“Any increase in the number of tests, especially RT-PCR tests, is a welcome move. And, the Delhi government is actually doing better than most state governments when it comes to the number of tests. However, there is more that needs to be done. Currently, the government does about 17 tests to get a positive result; on national level this number is anywhere between 11 and 15. In some countries it is as high as 100 to 200 tests for each positive case,” said Dr Lalit Kant, former head of the department of epidemiology and infectious diseases at ICMR.

He also added that the government needs to verify a higher proportion of the tests done using RT-PCR. “Currently, a very small percentage of those undergoing rapid antigen tests get a second confirmatory RT PCR tests. This proportion needs to be increased. Anyone who is symptomatic but tests negative should be tested using RT-PCR,” he said.

Along with the number of tests, the number of cases being reported has also remained high. After a gap of over ten days, Delhi has been recording over 3,000 new cases a day for the last four days as the number of RT-PCR tests is increased by the government.

“If more RT-PCR tests are done, you are likely to pick up more cases because the test is more sensitive. This is the reason it is suggested that the less sensitive rapid antigen tests be used in containment zones for screening cases but the RT PCR tests be used everywhere elsewhere,” said Dr Rajinder K Dhamija, professor of medicine and head of department of neurology at Lady Hardinge Medical College.