Aggarwal AN, et al. - The diagnostic performance and the optimal diagnostic threshold of adenosine deaminase (ADA) in tuberculous pleural effusion (TPE) are assessed. Searching PubMed, Embase, and Cochrane Library databases, 2162 citations were retrieved, of these, 174 publications with 27009 patients were included. Outcomes suggest good diagnostic accuracy of ADA levels in pleural fluid in diagnosis of TPE; however, high risk of bias in all included studies was suggested. No specific inference could be drawn regarding the relative clinical utility of different diagnostic thresholds.