We compared the diagnostic utility of unstimulated pleural IFN-γ levels with several pleural antigen-specific T-cell IGRAs (early secretory antigenic target-6 and culture filtrate protein-10 (T-SPOT.®TB, QuantiFERON®-TB Gold In-tube), purified protein derivative (PPD) and heparin-binding haemagglutinin (HBHA)) in 78 South African TB suspects. Test results were compared against a clinical score and a reference standard. Unstimulated IFN-γ was the most accurate test for distinguishing TB from non-TB effusions in a high-burden setting. The antigen-specific T-cell IGRAs were limited by suboptimal accuracy and the inability to isolate sufficient mononuclear cells to perform the assay.
