This test measures hydrogen and methane levels in your collected breath samples: One baseline breath sample collected before drinking the sugar solution, and then 7 breath samples collected every 15 minutes after drinking the sugar solution.
Choose a challenge, scroll down to learn the difference:
Which challenge should you choose to test for SIBO:
Glucose is the most specific one, this means that if there is a significant peak within the 90min mark it will yeald a definite positive diagnosis. Unfortunately glucose can be absorbed very rapidly in the small intestine, in such a case the test will miss a possible overgrowth further down the small intestine, yielding a false negative result.
Lactulose is the most sensitive test, this means it will pick up an overgrowth at any point in the small intestine. Unfortunately this sugar is poorly absorbed in the small intestine, and can reach the cecum producing a spike in measured gases. Depending on the mouth to cecum transit time it might yield a false positive result becuase the spike in gases might be produced by bacteria in the cecum.
Taking 2 separate tests: Glucose and Lactulose will yield the most predictive (specific + sensitive) diagnosis of SIBO.
If you suspect the presence of SIBO but you are not able to estimate its location in the small intestine (if in the first part or further down) werecommend to use lactulose as a substrate.