Diagnostic value of pleural fluid adenosine deaminase activity in tuberculosis pleurisy

Abstract

Background: Diagnosis of tuberculosis pleurisies is difficult because of its nonspecific clinical presentation and insufficient traditional diagnostic methods. We investigated the use of adenosine deaminase (ADA) activity in tuberculosis pleurisies. Methods: A number of 85 patients were analyzed with exudative pleural effusions. Using the ROC curve, we determined the optimal cutoff for TB pleurisy. Results: A number of 58 exudative samples were nontuberculous (non-TB) and 27 were tuberculosis (TB). There was statistically significant difference (p<0.0001) between the means of pleural fluid ADA levels among the TB and non-TB populations. The prevalence of TB pleurisy in the studied population was 31%. Using the cutoff point equal to 35 for diagnosing TB effusions the sensitivity and specificity 70.3% and 91.3%, respectively. The positive predictive value (PPV) was 79.1% and the negative predictive value (NPV) was 86.8%. A pleural fluid ADA value <19 IU/L suggests that a tuberculosis effusion is highly unlikely. Conclusion: Pleural fluid total ADA assay is a sensitive and specific test suitable for rapid diagnosis of TB pleurisy.

Keywords

• adenosine deaminase
• tuberculosis pleurisy
• diagnostic value
• exudative