Discrimination of pleural effusions based on multiple biological parameters

ABSTRACT2.1 INTRODUCTIONConventional methods are not always capable of establishing the cause of pleural effusion, so alternative tests are needed. The aim of this study was to explore the role of combined function of biological markers such as N-terminal-pro-B-type natriuretic peptide (NT-proBNP), tumour necrosis factor-a (TNF- ?), C-reactive protein (CRP), procalcitonin (PCT) in discriminating different pleural effusion groups (exudative and transudative)2.2 METHODIn this prospective clinical study, 50 patients with pleural effusion were included. Blood and pleural fluid specimens were collected to the standart vaccumed tubes simultaneously and centrifuged 15 minutes at 3000rpm. Specimens were put into 2 ml tubes and stored at -80°C. Plevral effusions were classified as transudate or exudates according to the Light?s criteria. All biochemical measurements were performed on a selective, discrete, multichannel analyzer using standart methodology. Human TNF- ? in pleural fluid was measured by an immunoenzymometric assay, CRP levels were measured by the turbidimetric latex agglutination, PCT (procalcitonin) concentrations were determined using an immunoluminometric assay, proBNP levels were measured with the chemolusency method.Statistical analyses were performed with SPSS 17.0 (statistical package for social sciences)The Mann-Whitney U test for testing statistical difference between the medians was assessed. The cut-off value was established by using ROC (receiver operating characteristic) curve.32.3 RESULTS50 patients were evaluated, 28 patients were diagnosed as exudate and 22 patients were transudate. Our results show that; pleural fluid NT-proBNP levels were higher in transudates and reached statistically significance (p=0.000). CRP concentration level has been studied in pleural fluid and been found to be higher in transudates than in exudates. CRP concentration levels of >1,5mg/dl show a sensitivity (%67) and spesificity (%91) and a positive predictive value of 91% in the discrimination of exudative fluids from transudates.TNF- ? and PCT claimed as good biochemical markers of exudative fluids but our study showed no statistically significant correlation between transudates and exudates (p=0.26/p=0,29).Key Words: Pleural effusion,Transudative and Exudative fluids, Biological markers