Evaluation of rapid antibody test and chest computed tomography results of COVID-19 patients: A retrospective study

Abstract Background The coronavirus disease 2019 (COVID-19) continues to spread around the world. Therefore, rapid, simpler, and more accurate diagnostic tests are urgently needed to diagnose the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. The purpose of this study was to evaluate the SARS-CoV-2 IgM/ IgG rapid antibody test results in symptomatic patients with COVID-19 and their chest computed tomography (CT) data. Methods A total of 320 patients admitted to our hospital for different durations due to COVID-19 were included in the study. Serum samples were obtained within 0 to 7 days from COVID-19 patients confirmed by RT-PCR and chest CT scan. According to the SARS-CoV-2 RT-PCR results, the patients included in the study were divided into two groups: PCR positive group (n=46), and PCR negative group (n=274). Results Of the 320 COVID-19 serum samples, IgM, IgG, and IgM/IgG were detected in 9.4%, 3.1%, and 17.8% within one week respectively. IgG/IgM antibodies were not detected in 69.7% of the patients. In the study, it was determined that 249 (77.8%) of 320 patients had positive chest CT scans. Four (5.6%) of 100 patients with negative chest CT scan had IgM positive and 2 (2.8%) had both IgM/ IgG positive. IgM was detected in 23 (9.2%), IgG in 1 (0.4%) and IgM/IgG in 35 (14%) of chest CT scan positive patients. The rate of CT findings in patients with antibody positivity (n=97) was found to be significantly higher than those with antibody negativity. Conclusions The results of the present study show the accurate and equivalent performance of serological antibody assays and chest CT in detecting SARS-CoV-2 0 to 7 days from the onset of COVID19 symptoms. When the RT-PCR is not available, we believe that the combination of immunochromatographic test and chest CT scan can increase diagnostic sensitivity for COVID-19.