PROS1 and COVID-19: Based on the aforementioned findings, we conclude that: 1) immunoassays detecting IgG antibodies against SARS-CoV-2 N protein instead of S protein alone are more reliable, considering Sp and Se scores, and 2) chemiluminescent assays could be recommended as screening methods for the detection of anti-SARS-CoV-2 IgG antibodies in the general population (particularly when the expected seroprevalence is low), while ELISA assays are more reliable for the evaluation and follow-up of confirmed COVID-19 patients.