Recent figures show that tuberculosis (TB) is advancing and killing more than two million people annually, yet no breakthrough in rapid diagnostics is in sight. Volatile metabolites of Mycobacterium tuberculosis (MTB) may provide just that. It is well established that MTB produces nicotinic acid in vitro. We have converted the free acid into methyl nicotinate and detected statistically significant differences in the breath of smear positive patients compared with healthy (smear negative) subjects.