Quanterix Corporation announced that the Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for its Simoa SARS-CoV-2 N Protein Antigen Test that can be run on the Simoa HD-X Analyzer, a fully automated high-throughput immunoassay instrument. The Simoa SARS-CoV-2 N Protein Antigen Test detects the presence of the SARS-CoV-2 virus nucleocapsid protein (or N protein) which is known to be elevated in respiratory fluids during the initial acute phase of the infection. Direct detection of antigen proteins from the virus may be a more meaningful measure of infection status than detection of RNA by rRT-PCR because genetic material can linger even after the virus has left the body, resulting in increased risk of false positives. In clinical studies, the test demonstrated a sensitivity of 97.7% (positive percent agreement) and specificity of 100% (negative percent agreement) up to 14 days following onset of symptoms. Under the current EUA, the SARS-CoV-2 N Protein Antigen Test is intended for use with nasopharyngeal (NP) samples in individuals suspected of COVID-19 by their healthcare providers. Quanterix will be pursuing authorization for additional sample types, including nasal swabs, saliva, and capillary dried blood obtained from a fingerstick. Preliminary clinical research studies suggest the viral antigen may be readily detectable in asymptomatic and pre-symptomatic patients, and Quanterix is exploring extending the test to screening applications, home-based sample collection and pooling to enable larger scale testing. FDA authorization of the Simoa SARS-CoV-2 N Protein Antigen Test for NP samples is an important early step in a project funded by the NIH Rapid Acceleration of Diagnostics (RADx) initiative to apply Simoa digital biomarker technology to decentralized SARS-CoV-2 antigen detection in non-invasive sample types. An ultimate aim of this NIH program is to improve clinical laboratory tests that will increase the capacity of SARS-CoV-2 testing in the U.S.