Antibody pairs were screened on an integrated robotic system 8 used previously to test antibody performance directly on nitrocellulose. In this system, the Hamilton STAR automated liquid handling robot (Hamilton Company, Reno, NV, USA), camera (IDS UI-1460SE-C-H detector with a Tamron M118FM16 lens), custom plate that held up to 96 LFAs, and custom control software developed inhouse were combined to allow rapid screening of antibody pairs directly in LFA format. The robot used 8-channel pipetting for parallel application to LFAs and the camera for imaging. The custom control software applied 1 µL of conjugate mix (0.15% anti-nucleocapsid-antibody-latex-bead test line conjugate and 0.1% or 0.05% chicken-IgY-antibody-latex-bead control line conjugate in 50 mM borate, pH 8.5) to the conjugate pad of the LFA. After a 10-minute delay to let the conjugate mix dry, 75 µL of sample, nucleocapsid protein, or buffer (2.5% BSA in PBST or 2.5% BSA and 1% IGEPAL in 1× PBS) was added to the sample pad. Images were acquired 20 minutes after sample addition. For each antibody pair, for positive and negative samples, four technical replicates were run in rounds with rNP, and three technical replicates were run in the round with pooled clinical samples.