According to anti-SARS-CoV-2 seroresponse in patients with COVID-19 from Croatia, we emphasised the issue of different serological tests and need for combining diagnostic methods for COVID-19 diagnosis. Anti-SARS-CoV-2 IgA and IgG ELISA and IgM/IgG immunochromatographic assay (ICA) were used for testing 60 sera from 21 patients (6 with severe, 10 moderate, and 5 with mild disease). The main clinical, demographic, and haemato-biochemical data were analysed. The most common symptoms were cough (95.2%), fever (90.5%), and fatigue and shortness of breath (42.9%). Pulmonary opacities showed 76.2% of patients. Within the first 7 days of illness, seropositivity for ELISA IgA and IgG was 42.9% and 7.1%, and for ICA IgM and IgG 25% and 10.7%, respectively. From day 8 after onset, ELISA IgA and IgG seropositivity was 90.6% and 68.8%, and for ICA IgM and IgG 84.4% and 75%, respectively. In general, sensitivity for ELISA IgA and IgG was 68.3% and 40%, and for ICA IgM and IgG 56.7% and 45.0%, respectively. The anti-SARS-CoV-2 antibody distributions by each method were statistically different (ICA IgM vs. IgG, p = 0.016; ELISA IgG vs. IgA, p < 0.001). Antibody response in COVID-19 varies and depends on the time the serum is taken, on the severity of disease, and on the type of test used. IgM and IgA antibodies as early-stage disease markers are comparable, although they cannot replace each other. Simultaneous IgM/IgG/IgA anti-SARS-CoV-2 antibody testing followed by the confirmation of positive findings with another test in a two-tier testing is recommended.
【저자키워드】 Clinical and laboratory findings, Croatia, COVID-19 diagnostics, Anti-SARS-CoV-2 antibody response, Serological methods, Two-step testing approach, 【초록키워드】 COVID-19, serological test, IgG, IgM, fatigue, Symptom, cough, pulmonary, anti-SARS-CoV-2, ELISA, serum, sensitivity, anti-SARS-CoV-2 antibody, IgA, IgM/IgG, sera, Fever, Patient, COVID-19 diagnosis, Severity of disease, immunochromatographic assay, IgG ELISA, distribution, disease, moderate, patients, Diagnostic method, marker, IgM and IgG, Shortness of breath, Simultaneous, positive, analysed, were used, comparable, IgA antibody, statistically, patients with COVID-19, with mild disease, 【제목키워드】 approach, patients with COVID-19,