ICMR plans to increase rapid antigen-based tests as Covid-19 cases surge

As India witnessed an exponential rise in the number of coronavirus cases, the Centre along with the Indian Council of Medical Research are planning to use the rapid antigen-based COVID-19 method to push the more rigorous RT-PCR test for detection of the virus, Hindustan Times reported.

A senior official of the Indian Council of Medical Research (ICMR) said rapid antigen-based tests could help to determine an ongoing infection quickly.

“This is why it is a good tool that can be used for diagnosis of Covid-19 along with the RT-PCR testing. RT-PCR, while a gold standard in diagnosing Covid-19, needs a proper biosafety level 2 lab for analysis,” said the official on condition of anonymity to HT.

“Antigen based test is a rapid point-of-care test that can be done on the spot without posing a biosafety hazard as it doesn’t deal with analysing a live virus,” added the official.

The test gives the quick result as it detects the presence of a foreign substance in a person’s oral or nasal swab that triggers the production of antibodies, and, therefore, can find infections. However, these are non-confirmatory tests. The test could effectively detect COVID-19 positive patients, but those who come negative must go for an RT-PCR test for re-confirmation.

RT-PCR, or reverse transcription-polymerase chain reaction, look for the genome of the Sars-Cov-2 virus. But RT-PCR testing has limited availability because it requires a specialized lab for analysis. Also, it takes around five hours to get results.

The national capital rolled out antigen-based testing as Covid-19 cases rose in the past two weeks. The development necessitated the need to conduct large-scale quick testing to trace, treat, and isolate infected individuals.

ICMR provided 50,000 kits to the Delhi government and has asked other states to start antigen-based testing. Uttar Pradesh has launched the tests.

On Sunday, the only approved manufacturer of the antigen tests, South Korean SD Biosensor, said daily production had exceeded 200,000. The ICMR and the All India Institute of Medical Sciences, Delhi, validated the Standard Q COVID-19 Ag detection kit by SD Biosensor about a fortnight ago, HT reported.

“We are already producing about two lakh kits in a day, and even started supplying to eligible hospitals,” said CS Bedi, medical advisor, SD Biosensor to HT.

ICMR had released a document on June 25 detailing the need for rapid antigen tests. It stated in the document that the country needs to massively scale up testing capacity as the number of Covid-19 cases rise and lockdown restrictions are gradually relaxed.

“As India is lifting lockdowns in various parts of the country in a phased manner, it is expected to see an upsurge in cases of COVID-19 due to increased transmission of SARS-CoV-2 virus. Because of this, it is important to scale up testing capacity to the maximum possible levels,” the document said.

“The gold standard RT-PCR diagnostic test for COVID-19 has limitations in terms of widespread availability. Given this, there is an urgent requirement of reliable and convenient rapid point of care antigen detection assays with high sensitivity and specificity,” added the document, while inviting applications from manufacturers who produce the antigen-based kit.