Kerala’s total tests drop: Less antigen tests, and no climb in RT-PCR

After much criticism over its testing strategy, the Kerala government announced that it would rely on RT-PCR tests rather than antigen tests. But the move has come at the cost of total COVID-19 testing.
Kerala’s total tests drop: Less antigen tests, and no climb in RT-PCR
Kerala’s total tests drop: Less antigen tests, and no climb in RT-PCR
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Increasing the number of RT-PCR tests, considered the gold standard for COVID-19 testing, has been a constant demand of many health experts and the opposition parties in Kerala, especially during the peak of the second wave. Unlike the RT-PCR test, the rapid antigen test, which Kerala has largely relied on, has a quick turnaround time but the accuracy of its results have in the past been called into question. On September 10, however, Kerala Chief  Minister Pinarayi Vijayan announced a change in its COVID-19 testing strategy, stating that it would scale down the number of rapid antigen tests and rely on RT-PCR tests. The government made clear that antigen tests are ‘only for emergency purposes’ in hospitals and that unvaccinated persons if symptomatic or with co-morbidities should do RT-PCR tests.

But the new testing strategy has come at the cost of overall daily testing in Kerala. Official data shows that in the past one month, the number of Rapid Antigen Tests fell drastically from over 1.02 lakh on August 31 to 27,323 on September 30, even as there has been no considerable increase in the number of RT-PCR tests.

TNM looked at data from September 10, when the new testing policy was announced, until September 30.  According to data published by the Kerala government, the number of daily antigen tests has been falling from 68,766 tests on September 10 to 27,323 tests on September 30. However, the decrease in antigen tests has not been followed by a proportionate increase in RT-PCR tests.

In fact, data from the 30-day period (September 10 to 30) shows great fluctuation in the RT-PCR testing, swinging from as low as 58,318 on September 14 to a 10-day high of 86,343 on September 23. Although the daily RT-PCR tests crossed the 80,000 mark in six days during this period, this hasn’t reflected an increase in the total number of daily tests. In fact, the total number of daily tests only fell from over 1.51 lakh tests on September 10 to over 1.03 lakh on September 30. The overall tests include CB NAAT, True NAT, RT LAMP, and POST PCR, besides routine and sentinel testing (which are RT-PCR tests) and antigen tests.

While Kerala’s daily COVID-19 cases fell from 25,010 on September 10 to 15,914 on September 30, the positivity rate remained largely unchanged - with TPR being 16.52% on September 10 to 15.32% at the end of the month.

According to the Union Health Ministry, Kerala still reports the highest active COVID-19 cases (1.43 lakh as of September 30) in the country. Meanwhile, experts have expressed apprehension over Kerala’s present testing model. “The demand of the medical community has always been to increase the RT-PCR tests, not to reduce antigen tests," says Dr Arun NM, an internal medicine expert based in Palakkad. He also points to the case of Tamil Nadu, which predominantly relies on RT-PCR tests, and has a lower positivity rate of 1.7% (as of September 27) compared to Kerala's 11.60%.

"Observing data from the last two weeks, Tamil Nadu daily conducts more than one lakh RT-PCR tests. Notably, Kerala does not have the capacity to do more RT-PCR tests than it does at present. We are only able to achieve 80,000 RT-PCR tests on some days due to the private sector,” he points out.

Dr Arun also explains that antigen tests will come into use when schools reopen on November 1. "In Kerala, even now RT-PCR test results mostly take more than 24 hours. When schools reopen, antigen tests will largely be useful," he says, questioning the logic behind cutting down the number of antigen tests.

(With inputs from Shiba Kurian)

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