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. 2022 Dec 9;12(1):21338.
doi: 10.1038/s41598-022-25266-3.

Evaluation of the Access Bio CareStart rapid SARS-CoV-2 antigen test in asymptomatic individuals tested at a community mass-testing program in Western Massachusetts

Sara Suliman #  1   2 , Wilfredo R Matias #  3   4 , Isabel R Fulcher  5   6 , Francisco J Molano  4   7 , Shannon Collins  4 , Elizabeth Uceta  4 , Jack Zhu  4 , Ryan M Paxton  8 , Sean F Gonsalves  8 , Maegan V Harden  9 , Marissa Fisher  9 , Jim Meldrim  9 , Stacey Gabriel  9 , Molly F Franke  5 , Deborah T Hung  9 , Sandra C Smole  10 , Lawrence C Madoff  10 , Louise C Ivers  3   4   5   11
Affiliations

Evaluation of the Access Bio CareStart rapid SARS-CoV-2 antigen test in asymptomatic individuals tested at a community mass-testing program in Western Massachusetts

Sara Suliman et al. Sci Rep. .

Abstract

Point-of-care antigen-detecting rapid diagnostic tests (RDTs) to detect Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) represent a scalable tool for surveillance of active SARS-CoV-2 infections in the population. Data on the performance of these tests in real-world community settings are paramount to guide their implementation to combat the COVID-19 pandemic. We evaluated the performance characteristics of the CareStart COVID-19 Antigen test (CareStart) in a community testing site in Holyoke, Massachusetts. We compared CareStart to a SARS-CoV-2 reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) reference, both using anterior nasal swab samples. We calculated the sensitivity, specificity, and the expected positive and negative predictive values at different SARS-CoV-2 prevalence estimates. We performed 666 total tests on 591 unique individuals. 573 (86%) were asymptomatic. There were 52 positive tests by RT-qPCR. The sensitivity of CareStart was 49.0% (95% Confidence Interval (CI) 34.8-63.4) and specificity was 99.5% (95% CI 98.5-99.9). Among positive RT-qPCR tests, the median cycle threshold (Ct) was significantly lower in samples that tested positive on CareStart. Using a Ct ≤ 30 as a benchmark for positivity increased the sensitivity of the test to 64.9% (95% CI 47.5-79.8). Our study shows that CareStart has a high specificity and moderate sensitivity. The utility of RDTs, such as CareStart, in mass implementation should prioritize use cases in which a higher specificity is more important, such as triage tests to rule-in active infections in community surveillance programs.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Number of CareStart rapid antigen test administered by date (n = 666). The bar colors reflect the results of the rapid tests on different days.
Figure 2
Figure 2
Examples of images of CareStart rapid test showing variable band intensities.
Figure 3
Figure 3
N2 gene RT-qPCR Cycle threshold (Ct) values corresponding to positive and negative CareStart rapid antigen test results for all RT-qPCR positive samples (n = 52).
Figure 4
Figure 4
Calculated positive (left) and negative predictive values (right) based on the CareStart performance characteristics and different prevalence estimates of SARS-CoV-2 infections.
Figure 5
Figure 5
Individuals who enrolled in the study multiple times and had at least one positive gold standard RT-qPCR reference (n = 11). The point colors reflect the different combinations of RT-qPCR and CareStart rapid test results. The numbers above the point correspond to Ct values of the RT-qPCR.
See this image and copyright information in PMC

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