Quanterix has secured an emergency use authorisation (EUA) from the US Food and Drug Administration (FDA) for its Simoa SARS-CoV-2 N protein antigen test.

Simoa (single molecule array technology), an advanced digital approach to immunoassays, allows counting single molecules for protein biomarker research applications.

Designed to run on the Simoa HD-X analyser, the antigen test will help identify the presence of SARS-CoV-2 virus nucleocapsid protein (or N protein), which is said to be inflated in respiratory fluids during the initial acute phase of the infection.

According to the company, the antigen test showed a sensitivity of 97.7% and specificity of 100% up to 14 days following onset of symptoms, in clinical studies.

The EUA enables the SARS-CoV-2 N protein antigen test to use with nasopharyngeal (NP) samples in individuals suspected of Covid-19 by their healthcare providers.

Quanterix expecting authorisation for additional sample types

Quanterix is also expecting authorisation for additional sample types, including nasal swabs, saliva, and capillary dried blood obtained from a fingerstick.

The company is also planning to extend the test to screening applications, home-based sample collection and pooling to facilitate large scale testing.

Quanterix stated that the FDA authorisation of the antigen test for NP samples is a crucial early step in a project funded by the NIH Rapid Acceleration of Diagnostics (RADx) initiative to apply Simoa digital biomarker technology to decentralised SARS-CoV-2 antigen detection in non-invasive sample types.

Quanterix chairman, CEO and president Kevin Hrusovsky said: “Antigen viral levels, if precisely tested, are potentially a better measure of active infection, and for understanding the kinetics and distribution of viral load across different sample types over the duration of the infection, treatment and recovery.

“We are pleased to announce a test that not only provides high levels of sensitivity and specificity, but is economical, well suited for high throughput testing and utilizes a complementary supply chain helping efforts to scale testing.”

In December 2020, Quanterix secured EUA status from the FDA for its Simoa Semi-Quantitative SARS-CoV-2 IgG antibody test.