The comparative value of pleural fluid adenosine deaminase and neopterin levels in diagnostic utility of pleural tuberculosis.

INTRODUCTION: The aim of the present study was to evaluate and compare the diagnostic accuracy of pleura levels of adenosine deaminase (ADA) and neopterin for the differential diagnosis of pleural tuberculosis (TP).

PATIENTS AND METHODS: The study included 50 patients with TB, 27 patients with malignancies, and 24 patients with pleural effusion of non-tuberculous and non-malignant origin as controls. ADA and neopterin levels in pleural fluid were measured by spectrofotometric and ELISA method, respectively.

RESULT: Pleural neopterin levels were significantly higher in patients with pleural TB than patients with malignancy (p< 0.001). Pleural ADA levels were significantly higher in patients with pleural TB than patients with malignancy (p< 0.001) and patients with benign non-tuberculosis effusions (p< 0.001). The mean levels of ADA and neopterin in pleural effusion were evaluated according to their underlying diseases for the diagnostic accuracy. As for pleural TB receiving operating characteristic curves identified the following results; The best cut-off value for pleural neopterin was 4.7 U/L and yielded a sensitivity and specificity of 86% and 72.55%, respectively. Taking a cut-off value of 42 U/L for pleural ADA, the sensitivity and the specificity were found to be 88% and 68.63%, respectively.

CONCLUSIONS: In the diagnosis of pleural TB pleural neopterin level has a comparable sensitivity to pleural ADA activity. Both markers may find a place as a routine investigation in the coming days for early detection of TB. However, these tests should not be considered an alternative to biopsy and culture.