Swab-free transport as an optimized pre-analytical workflow for SARS-COV-2 amplification

Abstract

Introduction

Efficient detection of SARS-CoV-2 will continue to be an invaluable tool for pandemic control. Current instructions specify that the collection swab should be transported within its collection media to the laboratory. Developing a process whereby this swab is removed before transport to the lab would allow for improved automation and decreased manual manipulation of samples.

Methods

A proof of principle approach was taken by eluting viral particles from flocked swabs into collection buffer with and without a mucus background. Paired swab-free and swab-containing samples were transported to the laboratory and evaluated for SARS-CoV-2 (n = 28) or RNaseP (n = 6). SARS-CoV-2 amplification was performed using the Hologic Panther Fusion Aptima and RT-PCR assays.

Results

SARS-CoV-2 was detected in all proof of principle samples with Ct values indicative of dilution. The rare exception was for a few samples where the dilution pushed the viral load below the LOD. Paired samples were 100% concordant for SARS-CoV-2 and RNaseP detection.

Conclusion

Discarding the swab after inoculating the transport buffer is an appropriate pre-analytical modification. Adopting this approach can save up to 1 minute/sample. For labs processing more than 500 samples/day this equates to one full time equivalent shift/day.