PURPOSE: Tuberculous pleurisy (TPE) is still a diagnostic problem, especially in the regions with average and low incidence of tuberculosis as Vojvodina province in Serbia. In this study we have evaluated efficiency of ADA, culture and cytology of pleural effusion, and pleural biopsy for differential diagnosis of TPE and malignant effusion.
METHODS: This study included 121 patients, 54 with TPE and 67 with malignant effusion. Inclusion criteraia were: M. tuberculosis positive culture or pleural biopsy specimen, evidence of tuberculous granulomas or positive sputum cultures without other explanation for the appearance of effusion. Malignancy was diagnosed by cytology or biopsy specimen.
RESULTS: Cut-off for ADA activity in TPE was 49.19 IU, with specificity 70.4%, sensitivity 89.2%, PPV 84.4, NPV 78.4. Activity of ADA below cut-off of 16.19 IU suggests that tuberculous etiology is less likely (specificity 100%, sensitivity 38.5%, PPV 100%, NPV 57.4%). ADA effusion/serum ratio revealed cut-off 1.685 for the diagnosis of TPE (specificity 72.2%, sensitivity 84.6%, PPV 81.4, NPV 71.4). Specificity of cytology findings in diagnosis of TPE (lymphocyte rich effusion) was 88.1%, sensitivity 51.9%, PPV 77,8%, NPV 69,4%. Pleural biopsy revealed sensitivity 66,7%, specificity 100,0%, PPV 100,0%,NPV 78,8%. Cultures of effusion were positive for M. tuberculosis in 27.8% of cases.
CONCLUSION: ADA is specific and sensitive test for diagnosis of pleural tuberculosis even in a region with average incidence of pulmonary tuberculosis. When cost benefit relation is concerned low price of this test when compared to invasive surgical procedures makes it excellent diagnostic tool for TPE.
CLINICAL IMPLICATIONS: In the low-income countries with limited resources for diagnosis of pleural diseases rational use of diagnostic tools is absolute necessity. When compared to invasive procedures, ADA is still sensitive and specific enough, and the most importantly, cheap test for TPE diagnosis.
DISCLOSURE: Bojan Zaric, No Financial Disclosure Information; No Product/Research Disclosure Information