In order to develop the EliA SARS-CoV-2-Sp1 IgG assay, we tested 163 samples (serum and lithium heparin) from PCR-confirmed COVID-19 patients with the EliA SARS-CoV-2-Sp1 IgG test and set the cut-off to 10 EliA U/mL (low limit of equivocal zone set to 7 EliA U/mL). Here, SP1 is linked to COVID-19.