65 different clinical specimens from patients suspected of being infec
ted with Mycobacterium tuberculosis were examined by three different d
iagnostic methods. Two of these methods were the conventional microsco
pic and cultural examinations. The third, a modern chemotaxonomical me
thod is based upon the detection of tuberculostearic acid by GC-MS ana
lysis using selected ion monitoring (GC-MS/SIM). Comparison of the res
ults of the GC-MS analysis with those of the conventional methods has
indicated that tuberculostearic acid analysis can be used for diagnosi
ng tuberculosis under diagnostic routine conditions. The CC-MS method
is rapid, usually providing results within 20 hours or less.