Blood biochemical indicators, IgM and IgG antibodies in 56 confirmed and suspected COVID-19 cases

ObjectiveTo provide reliable indicators for effective prevention and control of COVID-19, we examined the biochemical indicators as well as anti-SARS-CoV-2 IgM and IgG antibodies in confirmed and suspected COVID-19 patients.

MethodsA total of 56 confirmed and suspected COVID-19 cases quarantined during January-March, 2020 in Gansu Provincial People′s Hospital and People′s Hospital of Xigu District, Gansu Province were included.Based on the results of nucleic acid testing and CT scan finding, they were divided into three groups: positive in both nucleic acid testing and CT scan finding; positive in nucleic acid testing but negative in CT scan finding; negative in both nucleic acid testing and CT scan finding.COVID-19 viral nucleic acid was detected and chest CT scan was performed.The following biochemical indicators were examined: total protein, albumin, total bilirubin, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyltranspeptidase, creatine kinase and lactate dehydrogenase.SPSS 22.0 statistical software was used to analyze the differences in the biochemical indicators among these three groups, as well as the temporal trend of IgM and IgG antibodies at different points of time.

ResultsThere were significant differences in the mean values of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase between these three groups (P < 0.05), whereas no significant difference in the mean value of total protein and albumin (P>0.05).ROC curve indicated that aspartate aminotransferase had the largest maximum area under the curve (AUC, 0.834), whereas alanine aminotransferase had the highest sensitivity (1.0) and total bilirubin had the highest specificity (0.927).Thus, aspartate transaminase provided the best prediction for the diagnosis of COVID-19, with sensitivity of 0.786, specificity of 0.854, and the maximum AUC of 0.834.In 12 of 16 confirmed COVID-19 patients tested IgG positive after 10 days of diagnosis, and 10 of 10 confirmed COVID-19 patients tested IgG positive after 14 days of diagnosis.

ConclusionAspartate aminotransferase may be the most useful indicator in the diagnosis of COVID-19.