A New Approach in Distinguishing Exudative and Transudative Pleural Effusions

Objective: Light’s criteria, which were accepted in 1972 for the differential diagnosis of pleural effusions as transudates or exudates, are widely used worldwide. It has been reported in various studies that Light’s criteria have lower specificity, and new recommendations have emerged. The discriminative ability of Light’s criteria and adapted formulas, which are our new proposal, were studied by Receiver Operating Characteristics (ROCs) analysis and Area Under the Curves (AUCs).Material and Method: These criteria were evaluated in 451 patients in our study. Of these cases, 151 had transudates, while 300 patients presented with exudates. Results: AUCs of Light’s criteria (P/Sprot, P/SLDH, PLDH) were measured as 0.931 (95%CI: 0.899-0.963), 0.936(95%CI: 0.904-0967) and 0.957(95%CI: 0.934-0.981), respectively, and the differences between the measured values were found to be statistically significant (p<.001). AUCs of our new adapted formulas (F-1, F-2, F-3) were found to be slightly higher than those of Light’s criteria, with the values of 0.987(95%CI: 0.976-0.998), 0.935(95%CI 0:.908-0.963) and 0.980(95%CI: 0.966-0.993), respectively, and the differences were also significant (p<.001). Conclusion: In our opinion, further studies are needed with a wider study population to determine the value of the new formulas in differentiating exudative and transudative pleural effusions. Proving our proposal would be useful in clinical practices.