Circulating tuberculostearic acid in tuberculosis patients.

Tuberculostearic acid (TBSA), a mycobacterial cell wall constituent, was measured in plasma samples using a highly sensitive high-performance liquid chromatography method. Plasma TBSA concentrations in patients with active tuberculosis (20 [0.5-347] nmol/l; n = 125) were higher than in patients with a variety of non-tuberculous pulmonary and extrapulmonary inflammatory conditions (0.1 [0-29] nmol/l; n = 116) and in healthy controls (0 [0-2] nmol/l; n = 102) (p = < 0.001). The calculated sensitivity, specificity, positive and negative predictive values for tuberculosis were 95.2%, 87.9%, 89.5% and 94.4%, respectively, indicating that assay of plasma TBSA might be a valuable complementary diagnostic tool.