Analysis of Haematological Parameters of Peripheral Blood in COVID-19 Patients with a Special Emphasis on D-dimer

Introduction: Coronavirus disease 2019 (COVID-19) is assessed by nasal / throat swab test, and further confirmed by Polymerase Chain Reaction (PCR) technique, albeit the dayto-day monitoring of COVID-19 patients depends largely on biochemical and haematological tests. There are differing results by various studies with respect to haematological parameters in Covid 19 infection. Hence this study was undertaken to analyse the haematological parameters in Covid 19 infection. Aim: To analyse the haematological parameters in peripheral blood samples of COVID-19 patients with a special emphasis on D-dimer. Materials and Methods: A prospective study was conducted on 75 Covid 19 patients, for six months from August 2020 to January 2021 in Department of Pathology, ESIC Medical College Sanath Nagar, Hyderabad, Telangana, India after obtaining ethical clearance from Institutional Ethical Committee. Patient blood samples were evaluated for complete haemogram, coagulation parameters, followed by correlation with various categories of D-dimer levels. Following demographic assessment, the patient data was then stratified into four distinct categories based on D-dimer levels. Pearson’s correlation test was used to analyse the correlation of D-dimer and fibrinogen levels with various haematological parameters. Stratification analysis of D-dimer categories with haematological parameters were assessed with respect to mean, standard deviation, median and interquartile range, significance (p-value) of which were calculated using Kruskall wallis test. A p-value of <0.05 was considered to be statistically significant. Results: 29 patients (38.7%) belonged to age range of 31-50 years category. Sixteen patients had normal D-dimer levels, 18 had mild elevation, moderately elevated D-dimer levels was noted in 26 patients, followed by 15 patients who had a severe elevation of D-dimer. Changes in Haemoglobin, Red Blood Cells (RBC) count and haematocrit were found to be significantly correlated with D-dimer levels, with p-values of 0.006, 0.021 and 0.010 respectively. Changes in Neutrophil (N) count, absolute Lymphocyte counts (L) and N:L ratio were also found to be having statistically significant correlation (p-values 0.032, 0.011, 0.001 respectively) with D-dimer levels. Conclusion: Assessment of haematological parameters can be a valuable tool in finding the severity of COVID-19 infection, thereby helping the clinicians in triaging, and treating the Covid 19 patient