▎ 摘　　要

NOVELTY - A protein or peptide comprising one or more amino acid sequences of SEQ ID NOs: 1-9 (sequences not given in the patent specification), is new. USE - The protein or peptide is useful in immunoassay diagnostic kit for detecting presence or absence of immunoglobulins M, G, or A against SARS-CoV-2 and determining total and/or separate content of immunoglobulins M, G, or A against SARS-CoV-2 (all claimed), and diagnosing SARS-CoV-2. ADVANTAGE - The protein or peptide enables to detect presence or absence of immunoglobulins against SARS-CoV-2 in an accurate and cost-effective manner high sensitivity and specificity, and enables to diagnose SARS-CoV-2 at an early stage. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) in vitro diagnostic method for detecting presence or absence of immunoglobulins against severe acute respiratory syndrome-coronavirus (SARS-CoV)-2, involves (a) contacting the proteins or peptides with biological sample to form an immune complex, and (b) detecting presence or absence of formed immune complex; and (2) immunoassay diagnostic kit comprising the proteins or peptides (antigens), wash buffer, incubation buffer, secondary antibody, developer solution, stop solution and a manual for using the kit.