Roche Diagnostics India launched its Quantitative antibody test- Elecsys Anti SARS CoV-2 S in January this year. The test since then has now been widely used in government and private hospitals and labs in various parts across the country. Roche Elecsys Anti SARS CoV-2 S test measures antibodies that could help detect a past natural infection or body’s immune response to the vaccine.
Roche Elecsys SARS CoV-2 S quantitative antibody test detects and quantifies antibodies in serum or plasma against the spike protein present on the surface of SARS CoV-2 virus. Spike protein is a common target for neutralizing antibodies. These type of antibodies prevent the virus from entering human cells thus protecting an individual. Hence, most COVID-19 vaccines contain the spike protein or at least a component of it so as to be able to produce an immune response in the form of antibodies and immune cells against it. The antibody immune response produced by vaccines can be quantified by measuring antibodies against the spike protein in a lab as done by the Roche Elecsys SARS CoV-2 S test.
As the neutralizing activity of antibodies is the closest link to potential protecting immunity, it becomes extremely relevant in the context of vaccination. The Roche Elecsys SARS CoV-2 S correlates extremely well with tests that detect such neutralization activity.
A quantitative antibody test reports amount or concentration of antibodies developed after vaccination or a\natural infection. On the other hand, a qualitative antibody test only gives a ‘Yes’ or ‘No’ answer though the results may be given in numbers. Thus, the qualitative test determines “if” and quantitative test answer the question “how much?” antibodies are produced. It is important to distinguish between the two while selecting an antibody test.
Quantitative antibody tests should report the concentration in standard universally acceptable units rather than arbitrary units or an index. This would allow a simple and uniform interpretation of test results. The units of the Elecsys Anti-SARS-CoV-2 S assay have an excellent correlation with and can be considered equivalent to the units of the WHO International Standard.
As new variants of SARS CoV-2 emerge, there is growing concern about their behavior and impact. It is essential that the chosen antibody test is able to detect antibodies developed against the variant virus, thus, indicating a past infection with SARS CoV-2.
Mr. Narendra Varde, Managing Director, Roche Diagnostics India, “The Elecsys Anti-SARS CoV-2 S assay was introduced right in time along with the commencement of COVID vaccination drive in India. The test, with its excellent accuracy, correlation to neutralization assays and standard reporting, is apt to not only assess exposure to SARS CoV-2 but also characterize the vaccine-induced immune response. With this introduction, we continue to fulfil our commitment of bringing novel, high medical value innovations to the country.”
Dr Pranav Desai, Managing Director, Desai Metropolis Health Services, “A quantitative antibody test can measure the immune response to COVID vaccination. This is especially relevant / of specific importance in individuals with suppressed immune systems due to diseases or medicines as the response to vaccine may be reduced in such individuals. Measuring antibodies to the two different proteins of the virus, N and S (spike) in most cases, can help differentiate individuals who have antibodies due to previous exposure to SARS-CoV-2 from the ones who developed antibodies only because of vaccination.”