One swab, two tests: Validation of dual SARS-CoV-2 testing on the Abbott ID NOW™

Laura E Burnes; Shawn T Clark; Elena Sheldrake; Amna Faheem; Betty P Poon; Natasha Christie-Holmes; Laura Finlay; Christopher Kandel; Michael Phan; Caylin Frankland; Trevor Lau; Jonathan B Gubbay; Antoine Corbeil; Kevin Katz; Robert A Kozak

doi:10.1016/j.jcv.2021.104896

One swab, two tests: Validation of dual SARS-CoV-2 testing on the Abbott ID NOW™

J Clin Virol. 2021 Aug:141:104896. doi: 10.1016/j.jcv.2021.104896. Epub 2021 Jun 12.

Authors

Affiliations

¹ Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada.
² Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
³ Shared Hospital Laboratory, Toronto, ON, Canada.
⁴ North York General Hospital, Toronto, ON, Canada.
⁵ Combined Containment Level 3 Unit, University of Toronto,Toronto, ON, Canada.
⁶ Michael Garron Hospital, Toronto, ON, Canada.
⁷ Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Public Health Ontario Laboratory, Toronto, ON, Canada.
⁸ Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Shared Hospital Laboratory, Toronto, ON, Canada; North York General Hospital, Toronto, ON, Canada; Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
⁹ Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Shared Hospital Laboratory, Toronto, ON, Canada; Sunnybrook Health Sciences Centre, Toronto, ON, Canada. Electronic address: rob.kozak@sunnybrook.ca.

Abstract

Background: Point-of-care tests (POCT) are promising tools to detect SARS-CoV-2 in specific settings. Initial reports suggest the ID NOW™ COVID-19 assay (Abbott Diagnostics Inc, USA) is less sensitive than standard real-time reverse transcription polymerase chain reaction (rRT-PCR) assays. This has raised concern over false negatives in SARS-CoV-2 POCT.

Objectives: We compared the performance of the ID NOW™ COVID-19 assay to our in-house rRT-PCR assay to assess whether dry swabs used in ID NOW™ testing could be stored in transport media and be re-tested by rRT-PCR for redundancy and to provide material for further investigation.

Methods: Paired respiratory swabs collected from patients at three acute care hospitals were used. One swab in transport media (McMaster Molecular Media (MMM)) was tested for SARS-CoV-2 by a laboratory-developed two-target rRT-PCR assay. The second was stored dry in a sterile container and tested by the ID NOW™ COVID-19 assay. Following ID NOW™ testing, dry swabs were stored in MMM for up to 48 h and re-tested by rRT-PCR. Serially diluted SARS-CoV-2 particles were used to assess the impact of heat inactivation and storage time.

Results: Respiratory swabs (n = 343) from 179 individuals were included. Using rRT-PCR results as the comparator, the ID NOW™ COVID-19 assay had positive (PPA) and negative (NPA) percent agreements of 87.0% (95% CI:0.74-0.94) and 99.7% (95% CI:0.98-0.99). Re-tested swabs placed in MMM following ID NOW testing had PPA and NPA of 88.8% (95% CI:0.76-0.95) and 99.7% (95% CI:0.98-0.99), respectively.

Conclusions: Storing spent dry swabs in transport media for redundancy rRT-PCR testing is a potential approach to address possible false negatives with the ID NOW™ COVID-19 assay.

Keywords: Abbott ID NOW™ COVID-19; COVID-19; Point-of-care testing; SARS-CoV-2.

MeSH terms

COVID-19 Testing
COVID-19*
Humans
Point-of-Care Testing
SARS-CoV-2*
Sensitivity and Specificity
Specimen Handling