The Role of Neutrophil to Lymphocyte Count Ratio in the Differential Diagnosis of Pulmonary Tuberculosis and Bacterial Community-Acquired Pneumonia: a Cross-Sectional Study at Ayder and Mekelle Hospitals, Ethiopia

Background: The differential diagnosis of pulmonary tuberculosis and bacterial community-acquired pneumonia is often a challenging phenomenon. The neutrophil to lymphocyte count ratio, a suitable indicator of inflammation, has been demonstrated to be a useful biomarker for predicting bacteremia. The main aim this study is to evaluate the role of neutrophil to lymphocyte count ratio in the differential diagnosis of pulmonary tuberculosis and bacterial Community-Acquired Pneumonia at Ayder and Mekelle hospitals, Mekelle, Ethiopia. Methods: A hospital based cross-sectional study was conducted from February to May 2017 on a total of 146 patients at Ayder and Mekelle hospitals. After taking written informed consent, study participants were interviewed for a detailed history and 5 mL of blood was collected for hematological analysis. Pulmonary tuberculosis was diagnosed by using Ziehl-Neelsen and Gene X-pert. Community acquired pneumonia was diagnosed using sputum culture. Student's t-test, Pearson's chi-square test, and receiver operating characteristics curve analysis were used. A p-value < 0.05 was considered statistically significant. Results: The neutrophil to lymphocyte count ratio and eythrocyte sedimentation rate were significantly higher in pulmonary tuberculosis patients than bacterial community-acquired pneumonia patients. Neutrophil to lymphocyte count ratio and eythrocyte sedimentation rate with cutoff values of >= 2.72 and >= 39, respectively, showed the highest area under the curve (AUC = 0.69; 95% CI: 0.62, 0.77). Conclusions: Neutrophil to lymphocyte count ratio and eythrocyte sedimentation rate together at a time with their respective cutoff values gave a 69% accuracy in differentiating pulmonary tuberculosis from bacterial community-acquired pneumonia. Therefore, neutrophil to lymphocyte count ratio and erythrocyte sedimentation rate can be used in differentiating pulmonary tuberculosis from PTB patients from bacterial Community-acquired pneumonia, especially in resource-limited settings.