Covid-19: How will rapid antibody tests for coronavirus work?

COVID-19

ndia on Thursday received 5 lakh units of serologic rapid testing kits from China. Dr Raman R Gangakhedkar of the Indian Council for Medical Research (ICMR) said that these testing kits — meant for novel coronavirus — have been provided by two separate companies, Lieozon and Wanflo, and claim to be highly accurate.

The head of ICMR’s Epidemiology and Communicable Diseases-I Division, Dr Raman R Gangakhedkar also said that these tests are meant to detect anti-bodies, which means that they are essential for surveillance and not meant for early diagnosis.

“Serology kits are better known as rapid testing kits. If the infection enters my body, I will be able to see the virus on the nasal swab and the pharyngeal swab. If I wait for eight days, I will see symptoms because the presence of the virus will be the most in my throat and nose. Then it [the presence of virus] starts falling,” Dr Gangakhedkar explained.

He added, “If virus enters my body, my body will prepare a weapon to fight this virus which are known as antibodies. Antibodies are exactly the opposite of the virus which is why it disables the virus. There are types of antibodies, the first of these is IGM which does not stay for more than a few days. Detection of IGM antibody means that the infection is recent. When IGG antibody appears, I will know that my immune system is improving. If I see only IGG antibody and no IGM antibody, I can assume that this is an old infection.”

Explaining while the rapid anti-body test kits could not be used for diagnosis, Dr Gangakhedkar gave the example of chickenpox whose anti-bodies are so strong that they do not allow the disease to return to the body. However, he said, HIV antibodies do not protect humans against the virus.

“RT-PCR is the ultimate test for the novel coronavirus to date,” Dr Gangakhedkar said, while speaking at the daily joint press briefing by the ICMR-Ministry of Health-PIB on April 16. He further added, “When we will conduct rapid antibody tests, these will not be for early diagnosis. It is so because if we conduct the antibody test after 10 days or two weeks, these antibodies will appear in only 80 per cent of the patients. This is why these tests are not used for diagnosis but for surveillance.”

Dr Gangakhedkar said that periodic use of antibody tests will inform authorities about the spread of the infection in identified hotspots. It is not so that an antibody created to fight one infection can stave off other infections forever, he added.

Source : www.indiatoday.in

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