1. Sensitivity and potential utility of SARS-CoV-2 rapid antigen and nucleic acid amplification tests in the context of an elimination approach.
- Author
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Beaumont J, Nargesi MM, Smith S, Harte D, Smit E, Ussher J, and McAuliffe G
- Subjects
- COVID-19 epidemiology, Humans, New Zealand epidemiology, COVID-19 diagnosis, COVID-19 Serological Testing standards, Disease Eradication methods, Nucleic Acid Amplification Techniques standards
- Abstract
Aim: To assess the sensitivity and potential utility of five RATs and the IDNow, Liat and Oxsed nucleic acid amplification tests (NAATs) in our population., Method: 39 retrospective and contrived SARS-CoV-2 positive samples were tested in parallel by standard RT-PCR and RAT. A second group of 44 samples was tested by standard RT-PCR, rapid RT-PCR and two isothermal NAAT assays. Limit of detection was compared at RT-PCR cycle thresholds for all assays., Results: We found that the Cobas Liat RT-PCR had 100% concordance with conventional RT-PCR, whereas the sensitivity of other rapid NAAT assays was less at lower viral loads indicated by Cts >30 (p=0.042) and the RATs at Cts >25 (p<0.001). When applied to New Zealand testing scenarios, IDNow or Oxsed NAAT could miss up to 12% and RATs up to 44.3% of COVID-19 cases compared with the RT-PCR currently used at our laboratory., Conclusion: We found that the POC Cobas Liat, a platform that delivers a sample answer in 20 minutes, demonstrated equivalent performance to standard RT-PCR. However, the RATs and isothermal NAAT assays demonstrated reduced sensitivity, limiting their utility in New Zealand's currently very low prevalence setting., Competing Interests: Dr Harte reports non-financial support from Abbott Rapid Diagnostics Pty Ltd, Siemens Australia and Rapid Test & Track, Sydney (supply of RAT devices for the trial evaluation).
- Published
- 2021