Correlation of Neutrophil to Lymphocyte Ratio (NLR) and Monocyte to Lymphocyte Ratio (MLR) in Diagnosis of Bacterial Infection in Children with Acute Febrile Illness - A Retrospective Descriptive Study

Dr. Kruthi M, Dr. Nagajyothi S, Dr. Vinod Muniyappa, Dr. Mansi Kumar

Abstract: Objective: To determine the correlation between Neutrophil to Lymphocyte Ratio (NLR) and Monocyte to Lymphocyte Ratio (MLR) to bacterial infections in children presenting with acute febrile illness. Methods: Retrospective study of 127 children aged 1 month to 18 years, admitted with acute febrile illness over 3 month duration. Diagnoses were categorized as bacterial or viral based on clinical and diagnostic criteria. Neutrophil to Lymphocyte Ratio (NLR) and Monocyte to Lymphocyte Ratio (MLR) were calculated from complete blood counts. Median values were compared using Mann-Whitney U test. ROC curve analysis assessed diagnostic perfor-mance. NPV and PPV were calculated. CRP correlation and antibiotic usage were also studied using SPSS Software. Results: Among 127 patients, 92 were bacterial and 35 were viral. Median NLR in bacterial infections was 1.94 (IQR 1.15?3.30) and 1.06 (IQR 0.67?1.72) in viral (p<0.01). MLR medians were 0.33 and 0.19, respectively (p<0.01). NLR AUC was 0.70; MLR AUC was 0.66. NLR >1.5 showed 72% sensitivity and 61% specificity. NLR correlated moderately with CRP (r = 0.26, p = 0.005); MLR correlation was weaker (r = 0.14, p = 0.121). PPV of 86.7%, NPV 35.2% for NLR, MLR PPV of 83.6%, NPV 32.1% for MLR. NLR was slightly lower in those with prior antibiotic use. Conclusion: NLR and MLR are low-cost, accessible practical adjunct markers that aid in triage of acute febrile illness and in distinguishing bacterial from viral infections , especially where advanced diagnostics are limited.

Keywords: NLR, MLR, bacterial infection, CRP, fever, children, ROC curve

How to Cite?: Dr. Kruthi M, Dr. Nagajyothi S, Dr. Vinod Muniyappa, Dr. Mansi Kumar, "Correlation of Neutrophil to Lymphocyte Ratio (NLR) and Monocyte to Lymphocyte Ratio (MLR) in Diagnosis of Bacterial Infection in Children with Acute Febrile Illness - A Retrospective Descriptive Study", Volume 14 Issue 7, July 2025, International Journal of Science and Research (IJSR), Pages: 1911-1914, https://www.ijsr.net/getabstract.php?paperid=SR25728202413, DOI: https://dx.doi.org/10.21275/SR25728202413