As Karnataka struggles to scale up Covid-19 testing, mobile lab promises help

The number of Covid-19 tests being conducted by the state has failed to increase to a point where health officials can determine that the disease is under control. The deployment of mobile diagnostic and testing units to plug the testing gaps could help, city-based scientists said.

According to epidemiologists, an indicator of adequate testing is a consistently low test positivity rate, which is calculated as a ratio of positives and total tests conducted. The World Health Organization (WHO) says that the recommended test positivity rate is under 10%. The ICMR data shows that Karnataka’s Test Positivity Rate (TPR) is 1.9%. However, at the same time, the state’s tests per million of the population is only 8,613, which is not high enough to validate the TPR.

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As of June 24, the state has conducted only 5.39 lakh tests for a population sized 640 lakh.

A member of the state’s expert committee said that the decline in testing numbers is not because of a lack of testing kits, which he described “as being more in number than are needed”. However, low testing is attributable to several factors, including shortfalls in swab collection and execution at the state’s 77 testing centres.

Since achieving a daily peak of 15,728 tests on May 30, numbers had declined to as low as 5,362 on June 15. On June 24, however, 12,709 tests were conducted, the state Covid war room said. At the same time, a backlog of Covid-19 for which test results are still awaited has grown to 13,741, out of which the largest totals are in Bengaluru (2,874) and Kalaburagi (3,378), according to the war room.

Dr C N Manjunath, the nodal officer for testing, could not be reached to shed light on this backlog.

The testing gap has been exacerbated with the closure of testing facilities at Nimhans and at the Bangalore Medical College and Research Institute (BMCRI) on June 22, after staffers caught the disease. Both centres had been testing some 1,000 samples a day.

Mobile option

In this scenario, scientists and engineers involved in the development of a BSL-2+ mobile diagnostic and testing unit at the Indian Institute of Science (IISc) suggested that the deployment of mobile testing units could help fix the malaise.

Prof Sai Shiva Gorthi, of IISc’s Department of Instrumentation and Applied Physics, said that the development of the unit had originated out of a need to plug critical gaps in Covid-19 diagnosis and testing across the country.

“With the number of cases going up, the priority is to scale up diagnostic testing capabilities and cut-down turnaround times from sample collection to test results from one to three days to a few hours,” he said.

The mobile unit has been in development since the start of the state pandemic in March is said to be capable of carrying out 320 tests per day, 80 of them in one go. The unit, Dr Gorthi, explained is currently spread across a Tata Force Traveller van which is designed to collect swab samples from areas, and two Tata Winger vehicles - one to carry out RNA extraction and the other to conduct the RT-PCR test.