The Value of Recently Developed Formulae and Biochemical Parameters in Distinction of Pleural Effusions as Transudate vs. Exudate

A hundred recently diagnosed cases with pleural effusion were investigated to determine the diagnostic value of various biochemical parameters and Light's criteria in distinction of pleural effusions as transudate vs. exudate. In our study, the value of serum-effusion albumin gradient, cholesterol level of pleural effusion, pleural effusion/serum cholesterol ratio and of Kokturk formulae along with Light's criteria in the distinction of transudate vs. exudate was investigated. Pleural effusions of 75 cases were classified as exudate and 25 as transudate. Sensitivity and specificity of diagnostic criteria were found 100%, 48% for Light's criteria; 86%, 72% for serum/effusion albumin gradient; 77%, 96% for cholesterol level of pleural effusion; and 73%, 88% for pleural effusion/serum cholesterol ratio, respectively. When Kokturk formulae were applied, sensitivity and specificity were 98%, 84% for formula 1; 97%, 100% for formula 2 and 3, respectively. In distinction of transudate vs. exudate, Kokturk formulae had the largest area under the curve (AUC values 91.3%, 98.7% and 98.7% for formula 1, 2 and 3, respectively). Transudative pleural effusions of 11 diuretic using cases were misclassified as exudate according to Light's criteria. The best results were found with Kokturk formulae (formula 2) in our study that investigated different biochemical parameters. As a conclusion, Light's criteria can be insufficient in the distinction of transudate vs. exudate, particularly in diuretic using cases. In that case, serum-effusion albumin gradient, cholesterol level of pleural effusion and using Kokturk formulae can be helpful for the clinicians.