Test data sheds light on wide disparities among TN districts

Chennai tops with 3,096 tests per million population

The number of COVID-19 tests done per million population (tpm) varied widely among districts, with Chennai leading the pack with 3,096 tpm, and Tiruvallur coming in last with just 142 tpm.

According to data released by the Greater Chennai Corporation, the State capital was conducting a significantly higher number of tests than all other districts, with Theni coming in a distant second with 1,176 tpm.

Only 9 districts were testing at a rate higher than the State average of 694, while 28 districts were testing at a lower rate, indicating a significant variation in testing figures among districts. Of the 37 districts in all, only six were testing at a rate of over 1,000 tpm. Fifteen of the remaining 31 districts were performing less than 500 tpm.

A comparison of the rate of testing with the number of cases showed a skewed correlation between the two in several districts. While certain districts with a fairly high number of cases were testing at a lower rate, the converse was also observed in a small number of districts, which had fewer cases and were testing at a relatively higher rate. Tiruvallur had the poorest testing rate, despite having reported 52 cases as of Friday. Other districts that were in the bottom 15 in terms of testing rate were Tenkasi, Ranipet, Chengalpattu, Nagapattinam and Erode, despite all of them finding a place among the top 20 in terms of the number of cases. On the other end of the spectrum was Perambalur, which had just five positive cases as of Friday, but was performing 1,101 tpm — the fifth-highest in the State. Similar trends were witnessed in Tirupattur and Dharmapuri.

An official in the Health and Family Welfare department said Tamil Nadu’s testing rate was definitely better when compared to many other States. “For every person testing positive, we trace and test 35 contacts on an average,” he said.

Chennai is all set to expand testing in containment zones.

“We are going to screen everyone with fever, cough and symptoms of influenza-like illness and severe acute respiratory infection,” the official said.

(All the figures were as of April 24, 2020)