Rapid antibody tests begin in city

Kolkata: The state Health department on Monday began conducting rapid antibody tests, starting from Belgachia slum in North Kolkata. A team from SSKM Hospital camped at a high school located adjacent to the slum and began the exercise. This slum falls in the red zone in the city and some residents had tested COVID-19 positive last week.

"Rapid antibody tests of more than 16 residents of the slum have been done on Monday. Today (Monday) was the first day and the camp could start only after noon. The number of tests will go up from Tuesday," a local source associated with the smooth running of the camp said. The parameters of distancing were maintained at the camp and the dwellers coming for the tests were made to sit at a reasonable distance from one another before entering the room to give their respective samples.

The ICMR guideline states that pooled testing will work in low COVID-19 prevalence areas — initially, in the places where the prevalence is less than 2 per cent. However, the method is not recommended in areas where the prevalence rate is more than 5 per cent.

"We will soon start tests in low COVID-19 prevalence areas, as per ICMR guidelines," said Chief Secretary Rajiva Sinha.

The rapid antibody test is a supplementary tool to assess the prevalence of the disease within a specific area or perimeter. The test will only be of utility after a minimum of seven days of onset of symptoms.

Unlike the RT-PCR, which detects the virus' genetic material (RNA) in swabs to diagnose a current COVID-19 infection, rapid tests detect antibodies in the blood and indicate if a person has been infected in the past and has developed immunity to the virus. It can show results within 30 minutes. Once a person tests positive after the antibody test, an RT-PCR test is done to confirm the result.

The results of the tests will not be revealed instantaneously even to the person, who has been tested, to prevent any panic mongering.