Hematological Markers as Predictors of COVID-19 Severity: A Prospective Study from South India

Introduction: Coronavirus disease 2019 (COVID-19) demonstrates wide clinical heterogeneity, ranging from mild illness to severe pneumonia, acute respiratory distress syndrome, and multiorgan failure. Early identification of patients at risk of severe disease is essential, particularly in resource-limited settings. Simple hematological and inflammatory markers may aid in early prediction of disease severity. Methods: A prospective observational study was conducted on 100 RT-PCRconfirmed COVID-19 patients admitted between December 2020 and October 2022 at Prathima Institute of Medical Sciences, South India. Patients were categorized as critical or non-critical according to World Health Organization (WHO) severity criteria. Hematological indices and inflammatory markers, including neutrophil-to-lymphocyte ratio (NLR), lymphocyte percentage, D-dimer, and interleukin-6 (IL-6), were analyzed and compared between the two groups. Results: The median NLR was significantly higher in critical patients compared to non-critical patients (6.35 vs 4.00; p Conclusion: Elevated NLR, lymphopenia, and increased IL-6 and D-dimer levels are reliable predictors of COVID-19 severity and may assist in early risk stratification and clinical decision-making.