Adenosine deaminase 2 in the diagnosis of tuberculous pleuritis

PURPOSE: We examined the usefulness of adenosine deaminase 2 (ADA2) in the diagnosis of tuberculous pleuritis. SUBJECTS: A hundred cases, 78 male and 22 female, with pleural effusion were examined. With regard to pleural effusion, 18 cases were transudate and 82 cases (9 tuberculous pleuritis, 27 lung cancer, 8 mesothelioma, 5 malignant diseases except lung cancer and mesothelioma, 5 benign asbestos pleurisy, 10 empyema, 10 parapneumonic effusion, one SLE, one parasitic infection, and 6 undetermined etiology) were exudates. The last 6 cases with unknown origin were excluded in this study. RESULTS: Pleural adenosine deaminase (ADA) was 90.4 +/- 22.4 U/l (mean +/- SD) and pleural ADA2 was 80.4 +/- 21.9 U/l in tuberculous pleuritis, both were significantly higher than those in non-tuberculous exudates (p < 0.001). In the diagnosis of tuberculous pleuritis, pleural ADA showed 100% sensitivity and 88% specificity, whereas pleural ADA2 showed 100% sensitivity and 91% specificity. CONCLUSION: Pleural ADA2 is useful in the diagnosis of tuberculous pleuritis, which has similar sensitivity and a little better specificity compared with pleural ADA.