Serological assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to support clinical diagnosis and epidemiological investigations . Recently, assays for large-scale detection of total antibodies (Ab), immunoglobulin G (IgG), and IgM against SARS-CoV-2 antigens have been developed, but there are limited data on the diagnostic accuracy of these assays . This study was a Danish national collaboration and evaluated 15 commercial and one in-house anti-SARS-CoV-2 assays in 16 laboratories . Sensitivity was evaluated using 150 samples from individuals with asymptomatic, mild, or moderate COVID-19, nonhospitalized or hospitalized, confirmed by nucleic acid amplification tests (NAAT); samples were collected 13 to 73 days either from symptom onset or from positive NAAT (patients without symptoms). Specificity and cross-reactivity were evaluated in samples collected prior to the SARS-CoV-2 epidemic from> 586 blood donors and patients with autoimmune diseases, cytomegalovirus or Epstein-Barr virus infections, and acute viral infections . A specificity of & #8805; 99% was achieved by all total-Ab and IgG assays except one, DiaSorin Liaison XL IgG (97.2 %). Sensitivities in descending order were Wantai ELISA total Ab (96.7 %), CUH-NOVO in-house ELISA total Ab (96.0 %), Ortho Vitros total Ab (95.3 %), YHLO iFlash IgG (94.0 %), Ortho Vitros IgG (93.3 %), Siemens Atellica total Ab (93.2 %), Roche Elecsys total Ab (92.7 %), Abbott Architect IgG (90.0 %), Abbott Alinity IgG (median 88.0 %), DiaSorin Liaison XL IgG (median 84.6 %), Siemens Vista total Ab (81.0 %), Euroimmun/ELISA IgG (78.0 %), and Snibe Maglumi IgG (median 78.0 %). However, confidence intervals overlapped for several assays . The IgM results were variable, with the Wantai IgM ELISA showing the highest sensitivity (82.7 %) and specificity (99 %). The rate of seropositivity increased with time from symptom onset and symptom severity.