Study of serum interferon gamma in tubercular pleural effusions

Abstract

Background: Pleural effusions (PEs) are a common reason for admission in Acharya Vinoba Bhave Rural Hospital, and in developing countries like India, tuberculosis (TB) is the most common cause of exudative PE. The diagnosis of tuberculous PE with standard analysis of pleural fluid is often inaccurate. Pleural tissue histopathology and culture for Mycobacterium tuberculosis are considered the gold standard, but the procedure is invasive, requires skilled clinicians, and does not provide immediate results. To address these limitations, we evaluated whether serum interferon gamma (IFN-γ) can be used as a diagnostic aid for tubercular PEs and to compare its efficacy with adenosine deaminase (ADA) and cytology of pleural fluid. Materials and Methods: The sample size was 86 patients aged 16 years and above and who were diagnosed having tubercular PE either on the basis of ADA or cytology or by both methods, and serum IFN-γ levels were evaluated in these patients. Results: Serum IFN-γ was significantly raised in patients with tubercular PE. Conclusion: Pleural fluid ADA and IFN-γ are almost equally sensitive in diagnosing tubercular effusion; however, in cases where obtaining pleural fluid or other diagnostic material is difficult, serum IFN-γ can be considered as aid in diagnosing TB.