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 10(3) 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 (152/169) and 71% of the clinically suspected cases (25/35), 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 (4/46) and 4.3% of bronchial washing samples (3/69) showed a positive
TSA. Therefore, the measurement of
TSA is useful as a rapid and sensitive method for diagnosing
pulmonary tuberculosis.