State to start serological survey with rapid antibody tests soon

Bhubaneswar: The state has decided to undertake serological survey using rapid antibody tests among targeted groups such as healthcare professionals and other frontline workers. This is in accordance with the revised ICMR guidelines issued on Tuesday and will help the government figure out the extent of the spread of the coronavirus.

The government is also planning to use rapid antigen tests on people with influenza-like illness, close contacts of Covid patients and immune-compromised patients seeking treatment for chronic illness. This strategy will compliment the ongoing use of the confirmatory RT-PCR test.

The plan will be fine-turned at a high-level government meeting on Thursday. “We will come out with a detailed micro-plan after a discussion with the ICMR’s Regional Medical Research Centre and other testing centres,” additional chief secretary (health) Pradipta Mohapatra said.

Sources said the government was planning to conduct antibody tests among asymptomatic police and security personnel, healthcare workers, staff members of municipal bodies, drivers of ambulances and public transport, and individuals in containment zones as part of the serological survey.

The test looks for presence of antibodies in the blood serum of a person to determine if and when they have been exposed to the novel coronavirus.

“This strategy will help us know the extent of the spread of the virus to understand if there is community transmission. Many people may have recovered after getting exposed. This, however, doesn’t help in finding out acute infection for immediate treatment,” said another health department officer.

The ICMR has approved the use of antibody tests using two methods: ELISA (enzyme-linked immunosorbent assay) and CLIA (chemiluminescence immunoassay).

The ICMR has approved some ELISA kits and has also given its nod for use of US FDA-approved ELISA and CLIA kits. The RMRC in Bhubaneswar is equipped to do antibody tests using both methods.

Antigen tests, on the other hand, are not as conclusive as RT-PCR but can be done quickly, without a specialised machine. South Korean firm SD Biosensor, which has a manufacturing unit in Gurugram’s Manesar, has developed a Standard Q Covid-19 Ag kit, which is ICMR approved.

The antigen test throws up true positives, but may also throw up a false negative. What this means is, if a person tests positive for Covid in an antigen test, it means he or she definitely has the virus. However, if a person tests negative, he or she should confirm this with an RT-PCR test.

Those with Covid symptoms and asymptomatic high-risk people — patients in hospital or on chemotherapy or waiting for organ transplant or elderly people with diabetes, lung, heart and kidney ailments, any patient undergoing surgery and non-surgical intervention such as bronchoscopy, dialysis and endoscopy — can undergo the antigen test.