Coronavirus treatment: ICMR unveils list of approved ELISA antibody testing kits

After advising states to conduct sero-survey (a test of the blood serum of a group of individuals) last week to measure coronavirus exposure, the Indian Council of Medical Research (ICMR) on Wednesday released a list of validated ELISA testing kits to detect antibodies against COVID-19. The apex medical body has released a list of validated ELISA antibody testing kits with the names of  companies and manufacturers of these kits. It has also enlisted the purposes for which these kits have to be used.

The ICMR said that the ELISA tests are to be used for only two purposes - sero-surveys and survey among vulnerable or high-risk populations, including healthcare workers, frontline workers, or those in containment zones.

ELISA tests for sero-survey: These kits should be used for conducting sero-surveys to understand the proportion of population exposed to SARS-CoV-2 infection including asymptomatic individuals. Depending upon the level of sero-prevalence of infection, appropriate public health interventions can be planned and implemented for prevention and control of the disease. Periodic sero-surveys are useful to guide the policy makers.

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ELISA tests for survey among high risk or vulnerable populations: The testing should be used for survey among vulnerable or high-risk populations, like healthcare workers, frontline workers, immune compromised individuals or those in containment zones, to know who has been infected in the past and has now recovered.

ELISA, an acronym for enzyme-linked immunosorbent assay test, is a test which measures IgG antibodies present in the blood against the COVID-19. ELISA test kits are used to identify individuals who were infected by the disease.

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List of approved ELISA tests for detection of antibodies:

• COVID Kavach ELISA IgG: So far, the ICMR has approved three batches of these kits manufactured by Zydus Cadila Healthcare Ltd from Gujarat.
• Euroimmun Anti- SARS-COV-2 ELISA IgG: Manufactured by US-based Euroimmune US Inc. One batch of the kit has been approved by the ICMR.
• Erbalisa COVID-19 IgG ELISA: Developed by American firm Calbiotech Inc. One batch of the kit has also been approved by the ICMR.

IgG antibodies generally start appearing after two weeks of onset of infection, once the individual has recovered after infection and last for several months. The IgG test, however, is not useful for detecting acute infection but indicates episode of SARS-CoV-2 infection in the past.

By Chitranjan Kumar