Development and performance of a point-of-care rapid antigen test for detection of SARS-COV-2 variants

Highlights

• A unique rapid Sars-CoV2 antigen test was developed with two pairs of high-affinity monoclonal antibodies.

• Demonstrated high sensitivity for samples with cycle threshold values under 30.

• Positive Percent Agreement is over 85.7% and Negative Percent Agreement is over 99.7%.

• Able to detect omicron variant in clinical setting.

Abstract

Background

SARS-CoV-2 antigen-based tests are well-calibrated to infectiousness and have a critical role to play in the COVID-19 public health response. We report the development and performance of a unique lateral flow immunoassay (LFA).

Methods

Combinations of several monoclonal antibodies targeting multiple antigenic sites on the SARS-CoV-2 nucleocapsid protein (NP) were isolated, evaluated, and chosen for the development of a LFA termed CoV-SCAN (BioMedomics, Inc.). Clinical point-of-care studies in symptomatic and asymptomatic individuals were conducted to evaluate positive predictive agreement (PPA) and negative predictive agreement (NPA) with RT-PCR as comparator.

Results

In laboratory testing, CoV-SCAN detected 14 recombinant N-proteins of SARS-CoV-2 variants with sensitivity in the range of 0.2–3.2 ng/mL, and 10 authentic SARS-CoV-2 variants with sensitivity in the range of 1.6–12.5 TCID50/swab. No cross reactivity was observed with other human coronaviruses or other respiratory pathogens. In clinical point-of-care testing on 148 individuals over age 2 with symptoms of ≤5 days, PPA was 87.2% (CI 95: 78.3–94.8%) and NPA was 100% (CI 95: 94.2–100%). In another 884 asymptomatic individuals, PPA was 85.7% (CI 95: 42.1–99.6%) and 99.7% (99.0–99.9%). Overall, CoV-SCAN detected over 97.2% of specimens with CT values <30 and 93.8% of nasal swab specimens with the Omicron variant, even within the first 2 days after symptom onset.

Conclusions

The unique construction of CoV-SCAN using two pairs of monoclonal antibodies has resulted in a test with high performance that remains durable across multiple variants in both laboratory and clinical evaluations. CoV-SCAN should identify almost all individuals harboring infectious SARS-CoV-2.

Summary

Unique construction of a point-of-care rapid antigen test using two pairs of monoclonal antibodies has led to good performance that remained durable across multiple variants in laboratory and clinical evaluations. Test should identify almost all individuals harboring infectious SARS-CoV-2.