A suite of volatiles have previously been identified as specific markers of 
Mycobacterium tuberculosis metabolism in vitro. These markers - methyl 
phenylacetate, methyl p-anisate, methyl nicotinate, o-phenylanisole with the 
addition of methyl salicylate, may also be derived from other sources and 
confound development of a breath test for tuberculosis. To identify potential 
sources of these potential biomarkers food products, cosmetics, TB medication, 
environmental air and cigarette smoke were analysed for these markers using 
solid phase microextraction coupled with Gas Chromatography/Mass Spectrometry. 
Breath from healthy subjects, including smokers was also tested. Methyl 
salicylate was commonly detected, making this unsuitable as a specific marker 
for M. tuberculosis. Methyl nicotinate was detected repeatedly in cigarettes. 
Methyl phenylacetate was detected in 1.7% of healthy subjects and 
o-phenylanisole in just 1% of healthy breath indicating these may be more 
suitable for inclusion in the tuberculosis breath test due to their low 
"background" level. These results justify further clinical studies to further 
explore these markers as specific indicators of M. tuberculosis infection.