Background: As many patients may be unfit to undergo medical thoracoscopy, in addition to the low yield of closed pleural biopsy in malignant conditions, finding novel hematological or pleural fluid biomarkers to unmask the diagnosis of exudative pleural effusion and guide management plan becomes of increasing importance.
Aim of the study: This work aimed at assessing the role of neutrophil to lymphocyte ratio in either blood or pleural fluid as a simple biomarker in detecting the underlying etiology of exudative pleural effusion.
Patients and Methods: This cross sectional study took place at Bab Al-Sha'reia University Hospital in the period between February 2021 and February 2022. It included 100 patients with exudative pleural effusion according to Light's criteria. Patients were divided according to the underlying cause into three groups; 1) malignant pleural effusion group, 2) tuberculous pleural effusion group and 3) para-pneumonic effusion group.
Results: The mean pleural fluid neutrophil to lymphocyte ratio was significantly lower in tuberculous pleural effusion group compared with other groups. As well, the same ratio was significantly lower in malignant pleural effusion group than para-pneumonia effusion group (p <0.001). Similar findings were met when comparing the means of hematological neutrophil to lymphocyte ratio among the three studied groups.
Conclusion: Neutrophil to lymphocyte ratio in either blood or pleural fluid is an easily-obtained and cost-effective biomarker which can differentiate between malignant pleural effusion, tuberculous pleural effusion and para-pneumonic effusion.