COVID-19(10) Mild(7) SARS-CoV-2(7) reported(7) asymptomatic subject(5) Characteristics(5) ELISA assay(5) reference material(5) CLIA(5) S1/S2(5) Result(5) ELISA(5) evaluated(5) specificity(5) nucleocapsid(5) IgG ELISA(5) Vaccine-induced immunity(5) conjunction(5) antibody(5) patient cohort(5) evaluate(5) point-of-care(5) calibrated(5) Lateral flow device(5) LFIA(5) analytical(5) serum samples(5) sensitivities(5) tested(5) Laboratory(5)