Change in antigen norms ‘shuts out’ Indian firms - High false negative rates are worrying because such tests could contribute to spreading the infection

Industry body questions Centre’s decision to 'all of a sudden' change the required accuracy thresholds

Passengers undergo thermal screening at Bandra railway station in Mumbai.: (PTI)

G.S. Mudur   |   TT   |   New Delhi   |    21.12.20  :  An industry body has accused the Centre of abruptly increasing the accuracy thresholds for rapid antigen tests used to detect the novel coronavirus, effectively granting a South Korean company a monopoly and eliminating Indian companies from government orders.

The Association of Indian Medical Device Industry (AIMED) has questioned the Centre’s decision to “all of a sudden” change the required accuracy thresholds — a sensitivity of 84 per cent from 50 per cent and a specificity of 100 per cent from 95 per cent.

Sensitivity measures true positives while specificity measures true negatives in the tested samples. A sensitivity of 84 per cent and specificity of 100 per cent would mean the test should yield no more than 16 per cent false positives and zero per cent false negatives.

High false negative rates are worrying because such tests could misleadingly label infected people as “negative” and contribute to spreading the infection. The guidelines require that anyone with symptoms who tests negative should be confirmed as negative through the more reliable RT-PCR diagnostic test.

The association on Saturday told the Indian Council of Medical Research — the government agency designated to validate all Covid-19 tests — that the revised specifications for rapid antigen tests are “discriminatory” and favour a South Korean company.

The specifications for tenders in the government e-marketplace portal have been changed “to match the results” of Korea’s SD Biosensor’s new test approved by the ICMR, the AIMED said in a letter to ICMR director-general Balram Bhargava, the health ministry and other government departments.

Officials in the ICMR and the health ministry did not respond to queries from this newspaper seeking their perspective on AIMED’s concerns.

“Indian manufacturers will sit idle and not be able to participate in tenders while SD (Biosensor) will again get a monopoly with 100 per cent government tender business and sell this product at very high prices to government agencies,” AIMED wrote in the letter.

AIMED’s forum coordinator, Rajiv Nath, said the diagnostic test manufacturers appreciated the need to upgrade accuracy thresholds over time as technology improved, but were questioning the abrupt change, which came without any intimation and sought a match with the specifications of a single company.

The chief executive of one diagnostic company said the new 84 per cent sensitivity threshold for rapid antigen tests exceeded the 80 per cent sensitivity criterion set by the US Food and Drug Administration.

“Everyone views the US FDA as setting the gold standard — yet for this specific requirement, they have even surpassed the levels required by the US FDA,” said the executive, who requested not to be named because he did not want to appear critical of the Centre.

The South Korean company, according to AIMED, has supplied over 80 per cent of the rapid antigen diagnostic tests used by government agencies across the country. “They sold their product at over Rs 400 per test until several Indian players entered the market with tests costing Rs 50,” Nath said.

The rapid antigen tests, which look for viral proteins, are easier and faster but less reliable than the RT-PCR tests that look for viral genetic material. But many states have increased their use of the rapid antigen tests and the Union health ministry has urged states to confirm, whenever necessary, negative antigen tests with RT-PCR tests.

“Domestic companies have helped reduce the price but the new technical specifications appear designed to provide exclusive opportunities to the South Korean company,” the executive said.