Diagnostic Values of SARS-COV-2 Antibodies using Lifotronic ECL-8000

One of the most definitive diagnostic tests for COVID-19 infection is rRT-PCR. Another modality developed to diagnose COVID-19 infection is the antibody (serological) assay. This essay can be performed quickly and easily but requires high sensitivity and specificity. This study aims to analyze the diagnostic values of anti-SARS-CoV-2 IgM and IgG using Lifotronic ECL-8000 and the development of antibodies based on time after the onset of the symptoms of COVID-19 in patients with confirmed COVID-19 infection. The serum of the patients with confirmed COVID-19 infection by rRT-PCR was collected between day 1 and day 21 after the onset of the symptoms. Anti-SARS-CoV-2 IgM and IgG from each sample were measured using Lifotronic ECL-8000 to determine their sensitivity, specificity, PPV, and NPV. This assay detects IgM against SARS-CoV-2 N and SRBD proteins, as well as IgG against SARS-CoV-2 SRBD proteins. The anti-SARS-CoV-2 IgM serological assays using Lifotronic ECL-8000 indicated that IgM had 91.6% sensitivity, 87.03% specificity, 90.4% PPV, and 88.67% NPV. Meanwhile, the anti-SARS-CoV-2 IgG serological assays using Lifotronic ECL-8000 showed that IgG had 93.05% sensitivity, 88.88% specificity, 91.78% PPV, and 90.56% NPV. The development of antibodies was observed on days 0-7 after the onset of the symptoms, and the positivity rate of anti-SARS-CoV-2 IgM was higher than that of anti-SARS-CoV-2 IgG. Starting from day 8 after the onset of the symptoms, the positivity rate of anti-SARS-CoV-2 IgG increased and remained higher than that of anti-SARS-CoV-2 IgM. It was concluded that anti-SARS-CoV-2 IgM and IgG serological assays using Lifotronic ECL-8000 could be utilized to support the diagnosis of patients with suspected COVID-19 infection with high sensitivity and specificity.