COVID-19(27) SARS-CoV-2(22) IgG(13) assays(10) performance(10) symptom onset(10) diagnostic(10) respiratory(10) sensitivity(10) selected(8) Patient(8) serology(8) added(8) positive(8) RT-PCR(8) Serological assay(8) Diagnosis(7) immunoassay(6) Serology.(6) POCT(6) cross-reactive(5) point of care(5) Final(5) different time point(5) point-of-care(5) Serological testing(5) specificity(5) Combination(5) COVID-19 infection(5) COVID-19 diagnosis(5)