Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 May 26;8(7):ofab243.
doi: 10.1093/ofid/ofab243. eCollection 2021 Jul.

Performance and Operational Evaluation of the Access Bio CareStart Rapid Antigen Test in a High-Throughput Drive-Through Community Testing Site in Massachusetts

Nira R Pollock  1 , Kristine Tran  2 , Jesica R Jacobs  2   3 , Amber E Cranston  2 , Sita Smith  2 , Claire Y O'Kane  2 , Tyler J Roady  2 , Anne Moran  4 , Alison Scarry  4 , Melissa Carroll  4 , Leila Volinsky  4 , Gloria Perez  4 , Pinal Patel  2 , Stacey Gabriel  5 , Niall J Lennon  5 , Lawrence C Madoff  2   6 , Catherine Brown  2 , Sandra C Smole  2
Affiliations

Performance and Operational Evaluation of the Access Bio CareStart Rapid Antigen Test in a High-Throughput Drive-Through Community Testing Site in Massachusetts

Nira R Pollock et al. Open Forum Infect Dis. .

Abstract

Background: To facilitate deployment of point-of-care testing for severe acute respiratory syndrome coronavirus 2, we evaluated the Access Bio CareStart COVID-19 Antigen test in a high-throughput, drive-through, free community testing site using anterior nasal (AN) swab reverse-transcription polymerase chain reaction (RT-PCR) for clinical testing.

Methods: Consenting symptomatic and asymptomatic children (≤18 years) and adults received dual AN swabs. CareStart testing was performed with temperature/humidity monitoring. All tests had 2 independent reads to assess interoperator agreement. Patients with positive CareStart results were called and instructed to isolate pending RT-PCR results. The paired RT-PCR result was the reference for sensitivity and specificity calculations.

Results: Of 1603 participants, 1245 adults and 253 children had paired RT-PCR/CareStart results and complete symptom data. Eighty-three percent of adults and 87% of children were asymptomatic. CareStart sensitivity/specificity were 84.8% (95% confidence interval [CI], 71.1-93.7)/97.2% (95% CI, 92.0-99.4) and 85.7% (95% CI, 42.1-99.6)/89.5% (95% CI, 66.9-98.7) in adults and children, respectively, within 5 days of symptoms. Sensitivity/specificity were 50.0% (95% CI, 41.0-59.0)/99.1% (95% CI, 98.3-99.6) in asymptomatic adults and 51.4% (95% CI, 34.4-68.1)/97.8% (95% CI, 94.5-99.4) in asymptomatic children. Sensitivity in all 234 RT-PCR-positive people was 96.3% with cycle threshold (Ct) ≤25, 79.6% with Ct ≤30, and 61.4% with Ct ≤35. All 21 false-positive CareStart tests had faint but normal bands. Interoperator agreement was 99.5%. Operational challenges included identification of faint test bands and inconsistent swab elution volumes.

Conclusions: CareStart had high sensitivity in people with Ct ≤25 and moderate sensitivity in symptomatic people overall. Specificity was unexpectedly lower in symptomatic versus asymptomatic people. Excellent interoperator agreement was observed, but operational challenges indicate that operator training is warranted.

Keywords: COVID-19; SARS-CoV-2; antigen; diagnostic; point-of-care.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Distribution of cycle threshold (Ct) values in reverse-transcription polymerase chain reaction (RT-PCR)-positive children and adults by days post symptom onset. The Ct values for each RT-PCR-positive individual are shown; red circles indicate false-negative Access Bio CareStart results, and black circles indicate true-positive CareStart results. Participants whose symptoms started on the day of testing are indicated as Day 0. ASx, asymptomatic.
Figure 2.
Figure 2.
Correlation of cycle threshold (Ct) value with CareStart band strength. Correlation of Access Bio CareStart test band strength (1 = faint, n = 45; 2 = medium, n = 11; 3 = strong, n = 79, as interpreted by the first reader) and reverse-transcription polymerase chain reaction Ct value from a swab collected in parallel are shown for the 135 individuals with true-positive CareStart tests. Median Ct values were 24.7 (interquartile range [IQR], 21.8–27.8), 22.8 (IQR, 19.9–24.5), and 18.0 (IQR, 15.7–20.4) for Groups 1, 2, and 3, respectively.
See this image and copyright information in PMC

References

    1. Johns Hopkins University. COVID-19 dashboard by the center for systems science and engineering (CCSE) at Johns Hopkins University. Available at: https://coronavirus.jhu.edu/map.html. Accessed 12 February 2021.
    1. Centers for Disease Control. CDC COVID data tracker. Available at: https://covid.cdc.gov/covid-data-tracker/#testing_testsperformed. Accessed 12 February 2021.
    1. U.S. Food and Drug Administration. Individual EUAs for antigen diagnostic tests for SARS-CoV-2. Available at: https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19-em.... Accessed 10 February 2021.
    1. Krüger LJ, Gaeddert M, Köppel L, et al. Evaluation of the accuracy, ease of use and limit of detection of novel, rapid, antigen-detecting point-of-care diagnostics for SARS-CoV-2 [preprint ]. medRxiv 2020. doi: 10.1101/2020.10.01.20203836:2020.10.01.20203836. - DOI
    1. Iglὁi Z, Velzing J, van Beek J, et al. Clinical evaluation of the Roche/SD Biosensor rapid antigen test with symptomatic, non-hospitalized patients in a municipal health service drive-through testing site. Emerg Infect Dis 2021; 27:1323–9. - PMC - PubMed