Abstract
Background: Most of the patients of Coronavirus Disease-19 (COVID-19) presented with mild symptoms and recovered, but a considerable number of cases deteriorated and succumbed to death. They often present with hemostatic abnormalities mimicking disseminated intravascular coagulation with increased risk of thrombosis rather than bleeding. Hence, early prediction of disease severity by some easily available hematological parameters might be helpful to reduce mortality in COVID-19 cases.

Aim and Objectives: The aim of the study was to determine whether values of Prothrombin Time (PT), International Normalized Ratio (INR), Activated Partial Thromboplastin Time (APTT) and D-Dimer (DD) correlate with disease severity in COVID-19 and also to find out cutoff value of these parameters to predict disease severity.

Materials and Methods: This observational cross-sectional study was done on total 400 hospitalized COVID-19 adult patients where patients were categorized into moderate and severe cases as per guideline of Government of India. Patients with pre-existing coagulation disorder or receiving anticoagulant drugs were excluded from the study. PT, INR, APTT, and DD values of these two groups were evaluated and compared statistically to determine their significance and the cut-off value to predict severity.

Results: Among the measured blood parameters means of PT (P < 0.001), INR (P < 0.001) and DD (P < 0.001) found to be significantly higher in the severe group of patients compared to moderate ones and DD value ≥1.365 mg/L indicates severe disease. APTT showed no statistically significant association with severity.

Conclusion: PT and INR can be used as severity marker in COVID-19 patients; however, DD is the most reliable marker correlating with disease severity.

Key words: Coronavirus Disease-19; D-Dimer; International Normalized Ratio