Analysis of neutrophil to lymphocytes ratio (NLR), platelet to lymphocytes ratio (PLR) and Ct value as a prognostic tool in Covid-19 patients-A cross sectional study in southern Rajasthan

Abstract

Introduction: Covid 19 is the ongoing pandemic which has affected millions of people across the world. Till date the number of confirmed cases in India has crossed 70 lacs. The clinical symptoms vary from a mild flu like illness to a severe from leading to ARDS, CBC analysis is a widely available test which can prove helpful in stratifying patients with Covid 19 infection. Neutrophil to Lymphocyte Ratio (NLR), Platelet to Lymphocyte Ratio (PLR) and Ct values have been studied across the world as a screening tool for severity among patients with Covid 19 infection.Aim: This Study aims to analyze NLR, PLR ratio among Covid 19 patients and co-relate the severity of illness with viral load.Type of Study: Retrospective StudyMaterial and Methods: Records of 80 Positive patients of Covid 19 were analyzed. Demographic data was recorded on a pre designed proforma, along with laboratory parameters like CBC, NLR, PLR and Ct values.Results: Out of 80 patients analyzed, 61 were males and 19 were females. Hemoglobin ranged between 6.7 gm/dl to 15.7 gm/dl with a mean of 12.27 gm/dl. Total leucocytes count ranged from 2.9x 103/ cumm to 22.0x 103 /cumm with mean of 7.4 x103 /cumm. 5 out of 80(6.25%) patients had Leucopenia and 6 out of 80 (7.5%) patients had Leucocytosis. Platelet count ranged from 65000 to 6.39 lacs/cu mm. Thrombocytopenia was observed in 13 patients (16.0%), while thrombocytosis was seen in 2 patients (2.5%). Cycle threshold value ranged between 19.18 and 34.0 with a mean of 26.59. NLR was calculated and it ranged from 0.55 to 27.0 with 17 patients having NLR >3.3, 63 patients had a NLR less than 3.3. All 17 patients who had a NLR > 3.3 were males, 14 of them were > 40 years of age( 14/17) and rest 3 were between 20-40 years of age.11 patients had PLR > 180( i.e. 11 out of 80) and all of them also had NLR >3.3. Most of the patient had mild to moderate symptoms, only 14 out of 80 patients(17.5%) required ICU care during the course of illness and 11 of these (78.57%) patients had NLR >3.3 and PLR >180.Cycle threshold was < 24 in 13 out of 80 patients and only 4 of them (30.75%) required ICU care. Sensitivity of NLR, PLR & Ct value in predicting ICU care in our study is 78.57%, 64.28% and 35.75% respectively while specificity is 90.90%, 83.3% and 77.27% respectively.Conclusion: NLR value of > 3.3 and PLR value of > 180 are sensitive markers in assessing the progression of disease. Ct value should not be considered as an important tool in monitoring the disease