A Comparative Study between Pleural Fluid Cholesterol and Light’s Criteria in Differentiating Exudative and Transudative Pleural Effusion

Background/Aims: When the production and buildup of pleural fluid overwhelm its absorption, pleural effusion develops. Pleural effusions are classified as either exudates or transudates based on their pathogenesis. In order to treat the patient rationally, it is critical to make an appropriate etiological diagnosis. Discrimination between transudates and exudates using Light's criteria may require additional testing, however employing pleural fluid cholesterol makes diagnosis possible with only pleural fluid analysis.

Materials and Methods: This comparative study included 140 patients with pleural effusions. Pleural effusions were determined to be transudative or exudative based on etiological diagnosis. The sensitivity, specificity, positive predictive value, and negative predictive values of each test for the diagnosis of an exudative effusion were assessed.

Results: The pleural fluid cholesterol levels showed a sensitivity of 97.95%, a specificity of 95.23% (P < 0.0001), a positive predictive value of 97.95% and a negative predictive value of 95.23%. The ROC curve analysis (receiver operating characteristic curve) of pleural fluid cholesterol with a cut-off of 45 mg/dl showed an area under the curve of 0.986.

Conclusions: The pleural cholesterol level can be utilized as a biomarker to identify an exudative effusion and replace Light’s criteria. It also eliminates the need for simultaneous blood sampling.