[Evaluation of the diagnostic value of adenosine deaminase activity in tuberculous pleuritis].

OBJECTIVE: To investigate the clinical value of pleural fluid adenosine deaminase (ADA) activity in differentiating tuberculous pleural effusions (TPE) from malignant effusions. METHODS: The serum and pleural adenosine deaminase activity of 91 cases confirmed by pleural biopsy through medical thoracoscopy were retrospectively analyzed. TPE was confirmed in 49 cases and malignant effusion in 42 cases. The optimal cutoff for TPE was determined by using the ROC curve. RESULTS: The mean pleural ADA was significantly (t = 7.383, P < 0.01) higher in PTE (46 +/- 26) U/L as compared to malignancy (16 +/- 8) U/L, so was the pleural fluid/serum ADA ratio (4.1 +/- 4.0 vs 1.76 +/- 1.2, t = 3.852, P < 0.01), but there was no statistically significant difference between malignant and tuberculous effusion in serum ADA activity [(13 +/- 5) U/L vs (12 +/- 6) U/L, t = 1.582, P > 0.05]. The cutoff value of pleural ADA for PTE was 28.7 U/L, with a sensitivity of 75.5% and a specificity of 95.2%. CONCLUSIONS: Pleural fluid, but not serum, ADA activity, can be used for the differentiation between tuberculous and malignant pleural effusions.