Using a whole-blood interferon-{gamma} assay to improve diagnosis of tuberculous pleural effusion.

Tuberculous pleural effusion (TBPE) is treatable and curable, and hence it is important to establish the diagnosis and initiate treatment early. However, its diagnosis is not straightforward and depends on the demonstration of Mycobacterium tuberculosis in the pleural fluid or pleural biopsy specimen, or demonstration of caseating granulomas in the pleura. Due to the paucibacillary nature of this condition, sensitivity of pleural fluid smear for acid-fast bacilli is very low (0–1%) [1]. Culture is relatively sensitive (12–50%) [2], but is timeconsuming and requires standardised laboratories. The sensitivity of pleural biopsy ranges 39–80% [1, 3, 4] but this technique is invasive.