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Coronaviruses

Sensitive SARS-CoV-2 Antigen Assays Developed for COVID-19 Diagnosis and Tracking

Strategic Insights

— 1 min read

Researchers from the University of Pennsylvania have developed a high-sensitivity assay for detecting SARS-CoV-2 antigen in respiratory samples, enabling the quantification and tracking of antigen burden in individuals with COVID-19. This assay, known as the Microbubbling SARS-CoV-2 Antigen Assay (MSAA), has been shown to accurately identify positives and negatives with a positive percentage agreement of 97% and a negative percentage agreement of 97% in a clinical validation study. The MSAA may serve as a screening method in longitudinal studies to identify patients who are likely experiencing active rounds of ongoing replication and warrant close viral sequence monitoring.

Key Takeaways:

  • The researchers developed a high-sensitivity assay, the Microbubbling SARS-CoV-2 Antigen Assay (MSAA), for detecting SARS-CoV-2 antigen in respiratory samples.
  • The MSAA demonstrated a positive percentage agreement of 97% (95% CI 92%-99%) and a negative percentage agreement of 97% (95% CI 94%-100%) in a clinical validation study with 372 residual clinical NP swabs.
  • The assay enables quantitative and accurate detection of acute infections and quantification and tracking of antigen burden, which may be essential for identifying patients who are likely experiencing active rounds of ongoing replication.
  • The study found that antigen was detected for longer and variable periods of time in immunocompromised patients with hematologic malignancies.
  • The total microbubble volume, a quantitative marker of antigen burden, correlated inversely with cycle threshold values and days-after-symptomonset.

Statistics:

  • The MSAA demonstrated a positive percentage agreement of 97% (95% CI 92%-99%) in a clinical validation study.
  • The MSAA demonstrated a negative percentage agreement of 97% (95% CI 94%-100%) in a clinical validation study.
  • The total microbubble volume correlated inversely with cycle threshold values (r = -0.85, p < 0.001).
  • The antigen positivity rate in swabs decreased as days-after-symptom-onset increased, with a median of 10 days for immunocompetent individuals.

Sources:

  • Femtomolar Sars-cov-2 Antigen Detection Using the Microbubbling Digital Assay With Smartphone Readout Enables Antigen Burden Quantitation and Tracking. Clinical Chemistry, 2022;68(1):230-239.
  • NewsRx. New COVID-19 Study Findings Have Been Reported by Researchers at University of Pennsylvania (Femtomolar Sars-cov-2 Antigen Detection Using the Microbubbling Digital Assay With Smartphone Readout Enables Antigen Burden Quantitation and Tracking). Genomics & Genetics Weekly. March 11, 2022; p 471.

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