Evaluation of Hematological, Inflammatory and Coagulation Biomarkers as an Indicator of COVID-19 Severity

Introduction: The aim of this study is to investigate the relationship between the severity of coronavirus disease-19 (COVID-19) with hematological, biochemical and coagulation parameters. Materials and Methods: This study included 277 hospitalized patients who were diagnosed with COVID-19 by realtime polymerase chain reaction (PCR) analysis of nasopharyngeal swab sample between January and May 2021. According to the World Health Organization (WHO) COVID-19 severity classification, patients were divided into two groups as mild/moderate group (non-severe) and severe/critical group (severe). Demographic data of the patients and laboratory parameters at the time of hospitalization were evaluated retrospectively. Results: The neutrophil count was significantly higher in the severe group (p= 0.021), while the lymphocyte and thrombocyte counts were significantly lower (p< 0.001, p= 0.031, respectively). Neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, mean platelet volume-lymphocyte ratio were significantly higher in the severe group (p< 0.001, p= 0.001, p< 0.001, respectively), while lymphocyte-monocyte ratio was lower (p= 0.005). C-reactive protein (CRP), ferritin, D-dimer, fibrinogen and prothrombin time were significantly higher in the severe group (p< 0.001, p< 0.001, p= 0.004, p< 0.001, p= 0.033, respectively), albumin levels were lower (p< 0.001). Blood urea nitrogen-albumin ratio, CRP-albumin ratio, fibrinogen-albumin ratio (FAR) were significantly higher and lymphocyte-CRP ratio (LCR) was lower in the severe group (p< 0.001 for each). The area under the curve (AUC) of the LCR value was 0.747 in ROC analyzes performed between both groups. When the LCR cut-off value was 0.14, 86.9% sensitivity and 52.9% specificity were detected. When the cut-off value of CRP was 13.2 mg/L, 0.724 AUC was detected with 82.0% sensitivity and 57.1% specificity. FAR showed 59.3% sensitivity and 72.2% specificity at a cut-off value of 12.17 (AUC= 0.696). Ferritin showed 72.7% sensitivity and 55.6% specificity at a cut-off value of 189 ng/mL (AUC= 0.691). A strong correlation was found between FAR and CRP in the correlation analysis (r= 0.724, p< 1000). In addition, a relationship was found between FAR and ferritin (r= 0.454, p< 1000). Conclusion: These laboratory parameters can be used as suitable biomarkers to determine the severity of COVID-19. These can help clinicians identify potentially serious cases at an early stage and enable early medical management.