Over 24,000 samples collected for random antibody tests

NEW DELHI: The Indian Council of Medical Research’s (ICMR) has collected around 24,000 blood samples from 60 districts in 21 states over the past two weeks for a sero-survey (a test of blood serum) to check for exposure to the Sars-cov-2 virus that causes Covid-19 in general population.

The cross-sectional survey of adults aged 18 years or more will detect infection in the community by testing for the presence of antibodies against Sars-cov2 that are found in the blood of people who have recovered from it.

Representative samples were taken from 60 districts chosen from among four categories based on reported Covid-19 cases per million population -- zero, low (0.1-4.7), medium ( 4.8-10) and high (>10). Four hundred samples from 15 districts from each stratum were selected randomly, according to ICMR.

The first batch of about 70% samples was dispatched to a central lab in Tamil Nadu for analysis on Sunday, and the results are expected in about three weeks.

“By end of this week the Icmrnational Institute for Research in Tuberculosis in Chennai that has been identified as the central lab to do the analysis, should receive all samples,” said an ICMR official, on condition of anonymity.

This community-based survey will hold the key for getting several vital clues on the disease trend, testing and so on, experts said. “If more people have antibodies and never detected that means the infection is widely present. It is a good thing that only few are ending up with complications and death. Indirectly it is also a way of knowing whether enough tests are being done,” says Dr Girdhar R Babu, head, life course epidemiology, Public Health Foundation of India.

The blood samples will be tested for IGG antibodies using ELISA method .