Antibody ELISA tests play an important role in surveillance of COVID-19

The world over, countries are eagerly waiting for a vaccine to give their people protection against SARS-CoV-2. In the interim period, health officials are relying on serology (antibody) testing for public health decision making and bringing life back to normal.

Critical use of antibody tests

The presentation of symptoms and a positive RT-PCR test gives a confirmation of the COVID-19 infection. However, there is a large population that remains asymptomatic and hence undiagnosed. In fact, various studies conducted at different times during this pandemic, have indicated to a significantly large population in India being asymptomatic. And that has led to the speculation about whether or not these people can further transmit the virus. Obviously, this can be dangerous for India in the long run, if these asymptomatic carriers remain untraced.

This is where antibody testing plays an important role. While RT-PCR and antigen tests assess the viral load in infected patients; antibody test helps in identifying asymptomatic individuals. Thus, RT-PCR and antibody tests are both essential but not interchangeable.

Choosing the right antibody test

The Indian government opened the doors for antibody testing in early April and by May, ICMR announced that it would be conducting surveillance and antibody testing with ELISA. Today, the market is flooded with ELISA tests for antibody testing for COVID-19. However, it is very important to keep in mind certain key points while selecting a suitable kit. The first and foremost important criterion is the sensitivity and specificity of the assay. Assays with low sensitivity often miss out positive cases and therefore can give incorrect sero-status. A test with a sensitivity and specificity of 99% or more minimizes the chances of false results and is thus considered to be an accurate indicator.

It is also important for manufacturers to maintain batch-to-batch consistency of the kit, an important criterion that the ICMR is looking at, to approve only kits that give high quality results. Batch-to-batch consistency aids in maintaining proper reported data important for epidemiological studies.

As India further steps up its testing and tracking capabilities, it is important to select a kit that has a simplified protocol with minimum steps to save time and reduce manual errors. A kit for example, with ready-to-use reagents does not require reconstitution and dilution and thus makes it user-friendly. 

With a large number of tests being conducted at one go, laboratories prefer ELISA kits that are easily adaptable to automation. This considerably reduces the burden on technicians, allowing for large volumes of screening with consistent precision.

Implications for policy decisions

It is important to get data on the prevalence of COVID-19 not just for scientific studies but also to answer questions such as in which areas do we need to immediately ramp up medical facilities? Which regions need to be the first to receive the vaccine? 

ICMR has recognized antibody ELISA testing for a scientific approach to make informed public health decisions and ‘Getting back to Normal’ strategy.

While tracking the pandemic’s trajectory, an antibody testing can help the policy makers determine whether the curve is flattening or not. This is important to strategize reigniting of the economy. In the long-term antibody tests will help us apprehend a second wave of COVID-19 and tracking if the population has acquired herd-immunity.

Most importantly, once a vaccine is ready, antibody tests can help the government identify vulnerable population who haven’t developed antibodies and need a vaccine and going further, to know if the vaccine has been effective in that area.

Antibody testing across countries

The WHO has expressed support for countries conducting antibody studies to provide data important for doctors, epidemiologists and policy makers in both short and long term. Countries across the globe are relying on antibody tests to track the virus in the high-risk group such as elderly and front-liners, to understand if the population has entered the herd-immunity stage and for understanding the extent and risk associated with the infection. 

ErbaLisa COVID-19 IgG ELISA – a Made in India reliable test kit

As the demand for ELISA antibody testing increases, the onus is on the manufacturers to ensure accuracy, proper validation and consistency of the test kits. Transasia Bio-Medicals Ltd. is proud to introduce its MADE IN INDIA ErbaLisa COVID-19 IgG ELISA test kits with a proven sensitivity and specificity of >99%. The kit has been evaluated by National AIDS Research Institute (NARI),Pune and approved by Indian Council of Medical Research (ICMR) and are playing an important role in helping the front-liners test and track the spread. It offers a simplified protocol with in-well dilution and ready-to-use reagents and is automation-friendly.