26 March 2021 - - US-based digitized biomarker analysis specialist Quanterix Corp's (NASDAQ: QTRX) Simoa technology has been used in research studies to detect the SARS-CoV-2 virus in serum/plasma, dried blood microsamples and saliva samples obtained from polymerase chain reaction + COVID-19 patients, the company said.

Published in Nature Communications, the research study of these technologies offers further evidence that non-invasive antigen detection in blood or saliva samples, including from asymptomatic and pre-symptomatic individuals, can serve as an important complement to testing of nasal and nasopharyngeal swab samples.

In addition to the benefits of detecting COVID-19 during the pre-symptomatic window when transmissibility is known to be highest, measuring viral load in blood may be particularly relevant in the context of clinical studies, as an indicator of disease severity or progression, and potentially of therapeutic efficacy.

While current PCR-based testing remains the gold standard for COVID-19 detection, concerns have been raised with respect to false negatives associated with nasal and NP swabs, particularly in asymptomatic and pre-symptomatic patients.

According to data published in the Annals of Internal Medicine, on day five of infection the median time for symptom onset and the peak of viral transmission molecular tests show a 38% probability of producing a false result. Moreover, PCR-based supply chains have been strained by increased testing demands, requiring the need to evaluate new testing paradigms.

Harnessing the high-sensitivity and specificity of the Simoa HD-X Analyzer to quantitate the SARS-CoV-2 nucleocapsid protein and anti-SARS-CoV-2 spike IgG directly in the various sample matrices in this research test, which is authorized for use with NP swabs, but not yet authorized by the FDA for emergency use with saliva or DBS samples, the research team observed a more than 90% positive percentage agreement of COVID-19 positive patients and a more than 98% negative percent agreement in all matrices within seven days of a positive PCR test, using sample cohorts which included both asymptomatic and symptomatic patients.

The research also demonstrates an inverse correlation between nucleocapsid protein clearance and an increase in SARS-CoV-2 anti-spike IgG in all matrices, suggesting that an early and robust IgG response alleviates severe disease outcomes, even when high levels of viral nucleocapsid protein are initially present.

Quanterix is a company that's digitizing biomarker analysis with the goal of advancing the science of precision health.

The company's digital health solution, Simoa, has the potential to change the way in which healthcare is provided by giving researchers the ability to closely examine the continuum from health to disease.

Quanterix' technology is designed to enable much earlier disease detection, better prognoses and enhanced treatment methods to improve the quality of life and longevity of the population for generations to come.

The technology is currently being used for research applications in several therapeutic areas, including oncology, neurology, cardiology, inflammation and infectious disease. The company was established in 2007 and is located in Billerica, Massachusetts.