Pleural Cholesterol to the Diagnosis of Exudative Effusion

INTRODUCTION: Diagnostic approaches to patients with a pleural effusion must be precise because many procedures depend on the nature of the fluid in the effusion. To date, no biochemical test is considered an appropriate alternative to Light's criteria. This study compared the absolute pleural cholesterol (PC) level and the pleural cholesterol/serum cholesterol (PC/SC) ratio with Light's criteria to determine exudative pleural effusions. MATERIALS AND METHODOLOGY: This study was a case series of 100 consecutive patients with pleural effusions. The clinical parameters that were used to diagnosis an exudative effusion included the cholesterol level, a pleural cholesterol level ≥ 50 mg/dL, a pleural/serum ratio ≥ 0.4, and Light's criteria. The sensitivity, specificity, and positive and negative predictive values of each test for the diagnosis of an exudative effusion were assessed. RESULTS: A total of 79 patients were definitively diagnosed with an exudative effusion and were included in the trial and analyzed. The mean PC level in the exudates was 90.39 mg/dL. The PC levels demonstrated a sensitivity of 97.22%, a specificity of 85.71%, a positive predictive value of 98.59% and a negative predictive value of 75%. The PC/SC ratio demonstrated a sensitivity of 81.48%, a specificity of 57.14%, a positive predictive value of 93.61% and a negative predictive value of 28.57%. CONCLUSION: The pleural cholesterol dosage level and the pleural/serum cholesterol ratio can be utilized as unique biomarkers to identify an exudative effusion and replace Light's criteria.