For COVID-19 antigen detection, sample stability is a concern: in the studies published on the CORIS COVID-19 Ag Respi-Strip, the BIOEASY 2019-nCoV Antigen Rapid Test Kit, and the BIOCREDIT COVID-19 Ag test, samples were kept at 4°C or −70°C when testing could not be done immediately, which indicates the need for a cold chain (21, 35, 36). Here, RENBP is linked to COVID-19.