Comparison of interferon-gamma release assays and adenosine deaminase of pleural fluid for the diagnosis of pleural tuberculosis

Abstract

To compare the diagnostic performance of interferon gamma releasing assays (T-SPOT. TB) and adenosine deaminase (ADA) in pleural tuberculosis, and therefore to evaluate the value of T-SPOT. TB in a high tuberculosis burden country. From June 2011 to November 2012, 111 patients with pleural fluid in Beijing Chest Hospital, Capital Medical University were enrolled prospectively and categorized as culture/biopsy-confirmed pleural tuberculosis group (n = 59) and non-pleural tuberculosis group (n = 52). Patients with uncertain diagnosis and clinically diagnosed pleural tuberculosis were excluded from the study. Pleural fluid T-SPOT. TB and ADA measurements were performed, in addition to other routine laboratory tests. Continuous variables (spot forming cells, SFCs) were compared using nonparametric Mann-Whitney U test. Comparisons between proportions were performed using Chi-squared test. The receiver operating characteristic (ROC) curve and cut-off value of pleural fluid T-SPOT. TB were established according to spot forming cells (SFC) between culture/biopsy-confirmed pleural tuberculosis group and non-pleural tuberculosis group (216 SFC/10(6) pleural fluid mononuclear cells). The sensitivity of pleural fluid T-SPOT. TB and ADA was 91.5% (54/59) and 71.2% (42/59), respectively. The specificity was 90.4% (47/52) and 92.0% (46/50), respectively. The sensitivity of pleural fluid T-SPOT. TB was significantly higher than that of ADA (χ(2) = 8.045, P < 0.01). There was no significant difference of specificity between pleural fluid T-SPOT. TB and ADA (χ(2) = 0.000, P > 0.05). The area under the ROC curve was 0.912 for pleural fluid T-SPOT. TB and 0.903 for ADA. The sensitivity of combination diagnosis of ADA and pleural fluid T-SPOT. TB decreased to 67.8% (40/59), but the specificity increased to 100.0% (50/50). Pleural fluid T-SPOT. TB are relatively accurate supplementary assays for the diagnosis of pleural tuberculosis in this high tuberculosis burden country, and the combination of pleural fluid ADA and T-SPOT. TB is of diagnostic value.