Ayshan MAMMADOVA, Zuleyha GALATA, Zeynep YALÇINKAYA, Nilgun Yılmaz DEMİRCİ
Annals of Clinical and Analytical Medicine - 2026;17(4):335-340
Aim: This study aims to investigate the diagnostic role of the C-reactive protein to lymphocyte ratio (CLR) in identifying the etiology of pleural effusions, specifically in distinguishing between infectious and non-infectious causes through transudate-exudate analysis. Methods: A total of 106 patients who were evaluated for pleural effusion in our department were retrospectively analyzed. In addition to biochemical, microbiological, and cytological examinations of pleural fluid, CRP and lymphocyte levels were measured simultaneously in both serum and pleural fluid. Results: A total of 106 patients were included in the study, 78(73.6%) of whom were male. Pleural fluid was identified as exudative in 66(62.3%) cases and transudative in 40(37.7%) cases. In the infectious group, the pleural fluid and serum CLR were significantly higher compared to the non-infectious group (p<0.001;p<0.001). When the threshold value for pleural fluid CLR was set at 27, it exhibited a sensitivity of 89.2% and a specificity of 88.7% in differentiating between infectious and non-infectious pleural effusions (AUC 0.941,p<0.001).In the exudative group, the pleural fluid and serum CLR values were significantly higher compared to the transudative group (p<0.001;p<0.001). Conclusion: This study shows that CLR can support clinicians in identifying the cause of pleural effusions and distinguishing between infectious/non-infectious and transudative/exudative types. Further studies are needed to confirm its diagnostic value.
