Predictive Values of Haematological Parameters, Neutrophil Lymphocyte Ratio and Derived Neutrophil Lymphocyte Ratio on Disease Severity in COVID 19 Patients

ABSTRACT

Introduction: COVID-19 caused by SARS-CoV-2is a highly contagious disease. It is a complex systemic disease primarily involving therespiratory system. Patients usually have mild to moderate illness andpresent with flu like symptoms. However, a small group of patientsmay progress or present in a critical condition necessitating intensivecare. Early identification of risk factors associated with critical illnessmay aid in providing timely supportive care and access to theintensive care unit (ICU) when required.Aims &Objectives: To compare the CBC findings, NeutrophilLymphocyte Ratio (NLR), derived neutrophil lymphocyte ratio (dNLR), Platelet Lymphocyte Ratio (PLR) and Lymphocyte MonocyteRatio (LMR) in mild and severe categories of COVID 19 patients.Materials &Methods: Cases diagnosed as COVID 19 and admittedin the wards and ICU of GTB Hospital, Delhi were included. Sampleswere collected from 27 cases. The cases were divided in severe andmild categories. Blood was collected in EDTA vial and CBC wasdone using Automated Hematology Analyser. Data were entered inSPSS 26 and statistical analysis was done using same software.Result: NLR, dNLR values and TLC were found to be significantlyhigher (P< 0.05) in severe COVID-19 patients compared to mildCOVID-19 patients. Differences in platelet count, PLR and LMRvalues were not significant between the two groups. Using ROCcurve, a cut off value of 10,950 for TLC, 6.19 for NLR and 4.13 fordNLR were determined. Using these values TLC was found to be93.3% sensitive, 91.7% specific;NLR was found to be 73.3% sensitive, 72.7% specific;dNLR was found to be 80% sensitive, 81.8%specific in recognizing severe COVID 19 infections.Conclusions: NLR, d-NLR, PLR &LMR are readily accessiblebiomarker, which can be calculated based on a complete blood count.In our study, TLC, NLR and dNLR were found to be useful indetecting severe COVID 19 infections. TLC was the most sensitiveand specific marker in detecting severe COVID 19 patients followedby dNLR. NLR was less valuable than dNLR.