Detection of SIBO using the lactulose or glucose breath tests is done by measuring the levels of hydrogen (H2) and methane (CH4) gases using a BreathTracker SC analyzer (a machine manufactured by Quintron). These gases are produced by bacteria in response specifically to the lactulose or glucose substrate. Since humans do not produce either hydrogen or methane, these gases are evidence of bacterial fermentation of a food substance. This is why a preparatory diet 24 hours before taking a SIBO breath test is necessary, because the diet removes food that would feed the bacteria and ensures that the response observed is due to the bacteria consuming the substrate.
The BreathTracker SC uses solid-state sensors to analyze trace-gas concentrations of H2, CH4 and carbon dioxide (CO2) in alveolar (lung) breath samples from patients who take the SIBO breath test. The results for H2, CH4 are measured in parts per million (ppm) and CO2 in percent (%). The CO2 is used to detect sample contamination and ensure that the samples collected contain adequate alveolar breath.