Handling and accuracy of four rapid antigen tests for the diagnosis of SARS-CoV-2 compared to RT-qPCR

J Clin Virol. 2021 Apr;137:104782. doi: 10.1016/j.jcv.2021.104782. Epub 2021 Mar 3.

Abstract

Background: SARS-CoV-2 molecular diagnostics is facing material shortages and long turnaround times due to exponential increase of testing demand.

Objective: We evaluated the analytic performance and handling of four rapid Antigen Point of Care Tests (AgPOCTs) I-IV (Distributors: (I) Roche, (II) Abbott, (III) MEDsan and (IV) Siemens).

Methods: 100 RT-PCR negative and 84 RT-PCR positive oropharyngeal swabs were prospectively collected and used to determine performance and accuracy of these AgPOCTs. Handling was evaluated by 10 healthcare workers/users through a questionnaire.

Results: The median duration from symptom onset to sampling was 6 days (IQR 2-12 days). The overall respective sensitivity were 49.4 % (CI95 %: 38.9-59.9), 44.6 % (CI95 %: 34.3-55.3), 45.8 % (CI95 %: 35.5-56.5) and 54.9 % (CI95 %: 43.4-65.9) for tests I, II, III and IV, respectively. In the high viral load subgroup (containing >106 copies of SARS-CoV-2 /swab, n = 26), AgPOCTs reached sensitivities of 92.3 % or more (range 92.3 %-100 %). Specificity was 100 % for tests I, II (CI95 %: 96.3-100 for both tests) and IV (CI95 %: 96.3-100) and 97 % (CI95 %: 91.5-98.9) for test III. Regarding handling, test I obtained the overall highest scores, while test II was considered to have the most convenient components. Of note, users considered all assays, with the exception of test I, to pose a significant risk for contamination by drips or spills.

Discussion: Besides some differences in sensitivity and handling, all four AgPOCTs showed acceptable performance in high viral load samples. However, due to the significantly lower sensitivity compared to RT-qPCR, a careful consideration of pro and cons of AgPOCT has to be taken into account before clinical implementation.

Keywords: Accuracy; Handling; Rapid antigen test AgPOCT; SARS-CoV-2.

MeSH terms

  • Antigens, Viral / analysis*
  • COVID-19 / diagnosis*
  • COVID-19 / immunology
  • COVID-19 / virology
  • COVID-19 Nucleic Acid Testing / methods*
  • COVID-19 Testing / methods*
  • Humans
  • Nasopharynx / virology
  • Oropharynx / virology
  • Point-of-Care Testing
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / immunology
  • SARS-CoV-2 / isolation & purification*
  • Sensitivity and Specificity
  • Serologic Tests / methods
  • Specimen Handling / methods
  • Viral Load

Substances

  • Antigens, Viral