Covid-19 diagnosis: Antibody tests can be key

As the country has been in the third stage of coronavirus transmission when the virus spreads quickly within the community, experts have called for the immediate launch of widespread antibody tests to clearly understand the extent of infection.

The government is also considering initiating the method. It is taking opinions from health experts and reviewing the outcomes in other countries who have already used antibody tests for Covid-19 diagnosis. 

Several government officials said there were questions over the accuracy of this method which cast doubt over its usefulness.

Experts, on the flip side, said the error margin of this method was still not evident and many developed countries were using it for wide-scale testing.

The point on which both the parties seemed to have agreed is that the method is cheap, quick and easily accessible.

It would also help to detect those who are asymptomatic -- people who carry the virus but never develop any symptom.

Prof ABM Abdullah, the personal physician of Prime Minister Sheikh Hasina, said, "I think we should go for the antibody tests."

He said other countries have started it and pointed out that there was nothing to lose.

The experts said widespread antibody testing can be useful in identifying those have recovered or become immune to the virus. This could be useful for plasma therapy in future as well.

The World Health Organisation has cautioned that there's no evidence that serological tests can show whether a person has immunity or is no longer at risk of becoming reinfected.

The current method of testing, although useful, only detects people who are currently infected with the coronavirus but not who have already recovered.

Experts said antibody tests take only 15-20 minutes to produce results whereas PCR tests take at least four hours.

Md Nazmul Hasan, assistant professor of internal medicine at Bangabandhu Sheikh Mujib Medical University, said though there was confusion over the accuracy of this method, it was not proved utterly incorrect.

Many countries, including the US, South Korea, and India, are conducting antibody tests to bring more people under screening facilities.

Abul Kalam Azad, director general of Directorate General of Health Services, told The Daily Star they would go for the method once they get recommendations from experts.

Institute of Epidemiology Disease Control and Research adviser Mustaq Hossain said, "This test method should be applied only where there is community transmission."

Widespread use of this test may provide us with misleading results, he said.