[Use of pleural fluid to serum bilirubin concentration ratio for the separation of exudates from transudates]

ABSTRACT

Differentiation between exudates and transudates is the first diagnostic approach of a patient with pleural effusion. The aim of this study was to evaluate usefulness of pleural fluid to serum total bilirubin ratio for distinguishing exudates from transudates and to compare accuracy of this parameter with three other criteria pleural protein, lactic dehydrogenase [LDH], cholesterol and in relation to established etiology for differentiating exudates from transudates. We prospectively studied 50 patients with pleural effusion, 34 had exudates and 16 had transudates. Correlation of pleural fluid to serum bilirubin concentration ratio of 0.6 or more with the presence of an exudates as determined by other established criteria was statistically significant. Its sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and efficiency were 76%, 87.5%, 93%, 63% and 87%, respectively. Therefore pleural fluid to serum bilirubin ratio can be effective for separation of exudates from transudates. In addition the bilirubin ratio is more cost effective in terms of laboratory processing and is more readily available