Siemens Healthineers bags first US FDA EUA for semi-quantitative SARS-CoV-2 IgG antibody test

Siemens Healthineers has received FDA Emergency Use Authorization (EUA) for the SARS-CoV-2 IgG (COV2G) antibody test. Like all previous EUAs, the test has not been FDA cleared or approved but has been authorised by FDA under an EUA for use by authorised laboratories only for detecting the presence of antibodies against SARS-CoV-2, not for any other viruses or pathogens for the duration of the declaration that circumstances exist justifying the authorisation of emergency use of in vitro diagnostics for detection and/or diagnosis of COVID-19.

As per a company release, this is the first antibody test authorised with a semi-quantitative detection claim and the fifth antibody test from the company to receive EUA that offers sensitivity and specificity of greater than 99 per cent. The COV2G antibody test offers both a positive or negative result for IgG antibodies and reports a numerical result expressed as index value. The test also attained the CE-mark and is now broadly available globally, .

A positive or negative result for IgG antibodies provides insight into an individual’s prior exposure to SARS-CoV-2 virus. Importantly, a semi-quantitative result enables clinicians to gauge the level of IgG antibodies in a patient’s blood sample. With this numerical value, clinicians can establish a baseline and be better equipped to assess changes of an individual’s immune response to the SARS-CoV-2 virus. Comparison of numerical results will help determine how SARS-CoV-2 antibodies develop in an individual and persist over time. A semi-quantitative result is necessary to accurately establish the level of IgG that may be protective.

When an individual is infected with the SARS-CoV-2 virus, unique antibodies will develop at different stages of the infection. Whereas the Siemens Healthineers SARS-CoV-2 Total antibody test detects antibodies to IgM and IgG that are present both early and later during the immune response, the COV2G antibody test specifically detects IgG antibodies that persist, and are the basis for an individual’s longer term immune response. The combination of these tests provides a complete picture of a patient’s serological status for the most accurate results throughout his or her contiuum of care.

“Our high-quality antibody test helps clinicians assess the level of a person‘s immune response, which is an important tool to have at this stage of the pandemic,” said Deepak Nath, PhD, President of Laboratory Diagnostics, Siemens Healthineers. “Siemens Healthineers offers a robust portfolio of reliable tests to help support patient care and fight COVID-19.”

Highly accurate antibody test results support key decision-making for individuals and communities. Antibody tests have multiple uses as an adjunct to PCR tests to aid in clinical assessment, to help determine prior exposure to the virus, by detecting antibodies that may neutralise the virus, to potentially identify donors of convalescent plasma, for epidemiological purposes including establishing prevalence of disease in populations, and to potentially help verify effectiveness of vaccines as they become available.

Antibody tests from Siemens Healthineers are reportedly well-positioned to aid vaccine development efforts. The COV2G antibody test, and all SARS-CoV-2 antibody tests from Siemens Healthineers, detect antibodies to S1RBD. Multiple potential vaccines in development for SARS-CoV-2 include the spike protein, specifically S1RBD—a key protein on the surface of the SARS-CoV-2 virus—within their focus.

Among the considerations for accelerated vaccine approval, according to most recent FDA Guidance issued on June 30, 2020, validated serology testing in clinical trials may play a pivotal role in assessing surrogate endpoints such as immune response to a vaccine. This requires additional understanding of SARS-CoV-2 immunology and, specifically, vaccine immune responses that might be reasonably likely to predict protection against COVID-19 and post-marketing studies to affirm predicted efficacy. The COV2G test meets or exceeds FDA requirements.

The COV2G antibody test is available on an expansive installed base of analysers installed in the US and in countries that accept the CE mark worldwide. This includes the Atellica Solution and ADVIA Centaur XP and XPT families of analysers. Comparable tests for Siemens Healthineers Dimension Vista and Dimension EXL systems also are being pursued.

SARS-CoV-2 Total antibody assay [COV2T] that detects both IgM and longer-lasting IgG antibodies is available in India since June 2020. As per the company, it is currently being used by several clinical laboratories and institutions on company’s reliable high throughput automated chemiluminescence analysers including Atellica Solution, ADVIA Centaur and Dimension EXL series for sero-surveillance.