The diagnostic potential of pleural fluid cholesterol as a novel marker for tuberculous pleural effusion: A cross-sectional comparative study

Background and Aims: Pleural fluid cholesterol is a recognized marker to distinguish exudative and transudative effusion. However, the role of pleural fluid cholesterol in diagnosing tuberculous pleural effusion (TPE) has not yet been evaluated. This study aimed to explore the diagnostic potential of pleural fluid cholesterol as a novel biomarker for TPE. Methods This cross-sectional comparative study was conducted from February 2022 to January 2023. A total of seventy (35- biopsy-proven TPE, and 35-non-TPE) patients aged > 18 years were included in this study. Patients with nephrotic syndrome, lymphoma, chylothorax, blood diathesis, and patients who were on lipid-lowering agents were excluded from this study. The diagnostic utility of pleural fluid cholesterol to identify TPE was evaluated using the receiver operator characteristic (ROC) curve. Results The mean age of the TPE was significantly lower than the non-TPE (35.54 ± 14.13 vs 57.17 ± 17.99). TPE's mean pleural fluid cholesterol concentration was significantly higher than non-TPE (99.87 ± 23.82 vs 66.33 ± 36.89). ROC curve analysis demonstrated that at the cut-off of 69.85 mg/dL, pleural fluid cholesterol has a significant diagnostic value for the diagnosis of TPE (AUC = 0.72, sensitivity = 97.1%, specificity = 57.1%, PPV = 69.3%, NPP = 95.2%, and accuracy = 77.1%), and performance was similar to ADA (cut off = 29.95 IU/L, AUC = 0.73, sensitivity = 94.2%, specificity = 62.8%, PPV = 71.7%, NPP = 91.6%, and accuracy = 78.5%) Conclusion Pleural fluid cholesterol might be a potential novel diagnostic marker for the diagnosis of TPE.