Soluble Fas ligand is another good diagnostic marker for tuberculous pleurisy.

Soluble Fas ligand (sFasL) is abundant in effusions of tuberculous (TB) pleurisy; however, its diagnostic value has not been scrutinized. We collected pleural effusions from 79 patients, including 23 with TB pleurisy and 56 without TB, and measured sFasL, adenosine deaminase (ADA), and interferon-γ (IFN-γ) concentrations of each specimen. The median of the sFasL concentration of the TB group was 57.3 pg/mL, which was significantly higher than that of the non-TB group (27.4 pg/mL) (P < 0.001). When cutoff value was 39.85 pg/mL, the sensitivity and specificity of sFasL were 95.7% and 80.4%, respectively. The area under the receiver operating characteristic curve for sFasL was not significantly different from those of ADA and IFN-γ. Soluble FasL concentrations of TB patients were significantly higher than those of parapneumonic effusion subgroup (P = 0.039). In conclusion, pleural effusion sFasL is another good diagnostic marker for TB pleurisy.