Diagnostic value of pleural fluid adenosine deaminase among the patients with pleural tuberculosis

Purpose Extra-pulmonary tuberculosis occurs in about 10-20% of patients most commonly as tuberculous lymphadenitis or pleural effusion.Pleural uid Adenosine deaminase (ADA) activity considered as a useful biomarker for detecting pleural tuberculosis.The purpose of this study was to evaluate the diagnostic accuracy of pleural uid adenosine deaminase level in patients with pleural tuberculosis.Methods In this cross-sectional study, 113 patients with exudative pleural effusion with unknown underlying diagnosis, were enrolled.Physical examination, chest CT, measurement of ADA level of pleural uid, direct thoracoscopic examination, and biopsy of pleura were performed for all individuals.Results The diagnosis of tuberculous pleurisy was established in 40 individuals regarding the pathology report of biopsy samples.The mean ADA level of the TB and the non-TB group was 39.90±22.93IU/L and 30.74±38.27IU/L respectively, which was not statistically signi cant (P-value=0.167).Sensitivity, speci city, positive predictive value, and negative predictive value of ADA test were 35%, 86.30%, 58.33%, and 70.79%, respectively.Conclusion Based on low sensitivity and speci city of ADA test, in patients with unexplained exudative pleural effusion especially in those who were suspicious for tuberculous pleurisy, despite the low level of ADA, direct thoracoscopic pleural observation and multiple biopsies of pleura is highly recommended.