Pooled nasal matrix was collected via nasal swabs collected by in-lab volunteers. All volunteers were confirmed negative by RT-PCR. Negative nasal matrix was collected using either Puritan Sterile Foam Tipped Applicator (25-1506 1PF TT MC) or Puritan PurFlock Ultra Elongated Flock Swab (25-3806-U BT) depending on availability. Volunteers self-swabbed by inserting the swab until resistance was met, rotating four times, and placing the swab into 500 µL of PBS with 2% IGEPAL CA-630 (Sigma, St Louis, MO, I8896). Nasal matrix samples were kept at 4°C until use. 450 µL of each sample was removed from the sample collection tube with a pipette and combined with all samples collected, to a total of 14 swabs from 9 volunteers. Gamma-irradiated SARS-CoV-2 (52287, lot number 70033322 BEI Resources), was diluted into the pooled nasal swab immediately before running. 200 µL of sample was added to each cassette using an exact-volume transfer pipette (Globe Scientific 139116). After 30 minutes, strips were read on a commercial lateral low reader (AX-2X-S, Axxin, Australia). Strips were also read visually by volunteers blinded to the irradiated virus concentration.