ACE2 and COVID-19: Lastly, to ensure that the multiplex nature of the assay was not causing competition between beads for ACE2 which would have resulted in artificially deflated values, the assay was performed as both a singleplex (for all VOCs) and multiplex with 24 samples (19 COVID-19 infected, 5 pre-pandemic), with no difference in performance between the two bead compositions found (Figure S2).