Circulating Cell-Free DNA Level in Prediction of COVID-19 Severity and Mortality: Correlation of with Haematology and Serum Biochemical Parameters

Lymphocyte dysregulation in coronavirus disease-19 (COVID-19) is a major contributing factor linked to disease severity and mortality. Apoptosis results in the accumulation of cell-free DNA (cfDNA) in circulation. COVID-19 has a heterogeneous clinical course. The role of cfDNA levels was studied to assess the severity and outcome of COVID-19 patients and correlated with other laboratory parameters. The current case series included 100 patients with mild COVID-19 (MCOV-19) and 106 patients with severe COVID-19 (SCOV-19). Plasma cfDNA levels were quantified using SYBR green quantitative real-time PCR through amplification of the β-actin gene. CfDNA level was significantly higher in SCOV-19 at 706.7 ng/ml (522.6–1258) as compared to MCOV-19 at 219.8 ng/ml (167.7–299.6). The cfDNA levels were significantly higher in non-survivor than in survivors (p = 0.0001). CfDNA showed a significant correlation with NLR, ferritin, LDH, procalcitonin, and IL-6. The diagnostic sensitivity and specificity of cfDNA in the discrimination of SCOV-19 from MCOV-19 were 90.57% & 80%, respectively. CfDNA showed a sensitivity of 94.74% in the differentiation of non-survivors from survivors. CfDNA levels showed a significant positive correlation with other laboratory and inflammatory markers of COVID-19. CfDNA levels, NLR, and other parameters may be used to stratify and monitor COVID-19 patients and predict mortality. CfDNA may be used to predict COVID-19 severity with higher diagnostic sensitivity.