Testing fails to keep up as caseload soars

India’s covid-19 testing capacity has less than doubled in the past month, even as daily cases have jumped sixfold, a Mint analysis of government data shows. In Delhi, the worst-hit city, tests have come down in the past week, while Kerala is scaling up the fastest in response to rising infections.

The slow growth in testing, along with an increased infection rate, has bumped up India’s overall positivity rate to an all-time high of 20% as of Monday, from 4% a month ago.

This number, based on a seven-day rolling average, has crossed 30% in Delhi, Goa and Chhattisgarh, data on covid19india.org shows. Madhya Pradesh, Maharashtra, West Bengal and Kerala also fare worse than the national average.

An increase in testing capacity typically needs to match up to the rise in case-load to ensure all infections are detected.

“Early detection helps in quarantining confirmed cases, and so, not increasing testing capacity when the pandemic is in full swing could make infectious persons mobile, leading to further spread,” said Rijo M. John, an adjunct professor at Rajagiri College of Social Sciences, Kochi, pointing at high positivity rates. “Governments should at least double the testing numbers if they can’t triple.”

As of March end, India was testing 1.05 million daily samples, which has now grown to 1.65 million. This growth was led by some of the worst-hit states; but recent data show these states are either peaking in their testing capacity or growing very slowly.

Maharashtra increased daily tests from 120,000 a day to 250,000 in the first two weeks of April but has remained in the same range since then, despite there being no let-up in infections. West Bengal, which is holding assembly elections, has a population that’s just 20% smaller than Maharashtra’s. But even after a ramp-up, it is conducting just one-fifth of the latter’s tests.

In some states, such as Uttar Pradesh, private labs are reportedly claiming that the state government has asked them to limit testing, The Economic Times reported on 17 April.

By 11 April, Delhi had boosted testing to more than 100,000 a day, but this fell below 60,000 on Monday. This is a matter of concern because the national capital has been recording 350 deaths a day, with most hospitals filled to capacity and critical patients being turned away if they can’t produce a positive test result.

The stretched capacity is leading to delayed results of coronavirus tests in the city. Dr Harsh Mahajan, who runs a diagnostic chain in Delhi, said despite labs running extra shifts and adding machines, results were taking longer as demand exceeded supply.

John estimated that at the current positivity rate, each additional 10,000 tests could help detect 3,000 more cases every day. Indeed, Delhi’s daily caseload has come down from 28,395 on 20 April to 20,201 on 26 April with the decline in tests.