ABSTRACT
Differential diagnosis between Tuberculosis pleurisy and Non Tuberculoses pleural effusion can be sometimes difficult and needs invasive diagnostic methods. In recent years, several biological markers have been found to be diagnostic markers of Tuberculosis pleurisy. The aim of this study was assessment of the value of Gamma-Interferon in the diagnosis of TB pleurisy. We studied 70 patients with pleural effusion who had been admitted to Ghaem hospital, Mashhad University of Medical Sciences, Mashhad, Iran. Interferon gamma level was measured by "ELISA' method. The diagnosis of tuberculosis was based on microbiologic study of pleural fluid plus pleural biopsy. Altogether Twenty patients had tuberculosis pleurisy [44.44%], 21 patients had malignant pleural effusion [46.67%] and 4 patients had pleural effusion with various non TB non malignant etiologies [8.9%]. The sensitivity, specificity of Gamma-Interferon in TB pleurisy were 60% and 96% respectively. INF gamma is a valuable indicative marker for diagnosis of tuberculosis pleurisies' but we should consider situations with high level of INF gamma without any evidence of TB and also Tuberculosis pleurisy patients with INF gamma level lower than diagnostic threshold