Measurement of tuberculostearic acid in sputa, pleural effusions, and bronchial washings a clinical evaluation for diagnosis of pulmonary tuberculosis

Gas chromatography/mass spectrometry combined with selected ion monitoring was used to measure tuberculostearic acid (TSA), in sputum, pleural effusion, and bronchial washing. The detection limit corresponded to the amount of TSA eluted from as low as 103 tubercle bacilli. Sputa were collected from 169 patients with active pulmonary tuberculosis, 35 clinically suspected to be active, 53 with obsolete pulmonary tuberculosis, and 160 with pulmonary diseases other than tuberculosis. TSA was positive in 90% of the patients with active pulmonary tuberculosis (152169) and 71% of the clinically suspected cases (2535), respectively. In contrast, less than 10% of the patients with obsolete tuberculosis or other pulmonary diseases had a positive TSA. Pleural effusions and bronchial washings were also collected from patients with active tuberculosis and from those with other diseases, as the controls. TSA in pleural effusions and bronchial washings was detected in 24 of 32 patients and 15 of 22 patients with active tuberculosis, respectively. In those with pulmonary diseases other than tuberculosis, only 8.7% of pleural effusion (446) and 4.3% of bronchial washing samples (369) showed a positive TSA. Therefore, the measurement of TSA is useful as a rapid and sensitive method for diagnosing pulmonary tuberculosis.