PLoS ONE (Jan 2021)

Evaluation of a novel, rapid antigen detection test for the diagnosis of SARS-CoV-2.

  • Rainer Thell,
  • Verena Kallab,
  • Wolfgang Weinhappel,
  • Wolfgang Mueckstein,
  • Lukas Heschl,
  • Martina Heschl,
  • Stefan Korsatko,
  • Franz Toedling,
  • Amelie Blaschke,
  • Theresa Herzog,
  • Anna Klicpera,
  • Clara Koeller,
  • Moritz Haugk,
  • Anna Kreil,
  • Alexander Spiel,
  • Philipp Kreuzer,
  • Robert Krause,
  • Christian Sebesta,
  • Stefan Winkler,
  • Brenda Laky,
  • Marton Szell

DOI
https://doi.org/10.1371/journal.pone.0259527
Journal volume & issue
Vol. 16, no. 11
p. e0259527

Abstract

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BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) is currently finally determined in laboratory settings by real-time reverse-transcription polymerase-chain-reaction (rt-PCR). However, simple testing with immediately available results are crucial to gain control over COVID-19. The aim was to evaluate such a point-of-care antigen rapid test (AG-rt) device in its performance compared to laboratory-based rt-PCR testing in COVID-19 suspected, symptomatic patients.MethodsFor this prospective study, two specimens each of 541 symptomatic female (54.7%) and male (45.3%) patients aged between 18 and 95 years tested at five emergency departments (ED, n = 296) and four primary healthcare centres (PHC, n = 245), were compared, using AG-rt (positive/negative/invalid) and rt-PCR (positive/negative and cycle threshold, Ct) to diagnose SARS-CoV-2. Diagnostic accuracy, sensitivity, specificity, positive predictive values (PPV), negative predictive value (NPV), and likelihood ratios (LR+/-) of the AG-rt were assessed.ResultsDifferences between ED and PHC were detected regarding gender, age, symptoms, disease prevalence, and diagnostic performance. Overall, 174 (32.2%) were tested positive on AG-rt and 213 (39.4%) on rt-PCR. AG correctly classified 91.7% of all rt-PCR positive cases with a sensitivity of 80.3%, specificity of 99.1%, PPV of 98.3, NPV of 88.6%, LR(+) of 87.8, and LR(-) of 0.20. The highest sensitivities and specificities of AG-rt were detected in PHC (sensitivity: 84.4%, specificity: 100.0%), when using Ct of 30 as cut-off (sensitivity: 92.5%, specificity: 97.8%), and when symptom onset was within the first three days (sensitivity: 82.9%, specificity: 99.6%).ConclusionsThe highest sensitivity was detected with a high viral load. Our findings suggest that AG-rt are comparable to rt-PCR to diagnose SARS-CoV-2 in COVID-19 suspected symptomatic patients presenting both at emergency departments and primary health care centres.