SIBO Breath Test
Breath testing measures the hydrogen (H) & methane (M) gas produced by bacteria in the small intestine that has diffused into the blood, then lungs, for expiration.
Hydrogen and methane are gases produced by bacteria, not by humans.
The gas is graphed over the small intestine transit time of 2 or 3 hours & compared to baseline.
Patients drink a sugar solution of glucose or lactulose after a 1 or 2 day preparatory diet.
The diet removes much of the food that would feed the bacteria, allowing for a clear reaction to the sugar drink.
Two types of tests may be used: Lactulose or Glucose
Lactulose Breath Test
Humans can’t digest or absorb lactulose.
Only bacteria have the proper enzymes to digest or absorb lactulose.
After bacteria consume lactulose, they make gas.
If there is an overgrowth of bacteria, this will be reflected in the levels of hydrogen or methane.
This test is that it can diagnose overgrowth in the distal end of the SI, thought to be more common.
It cannot diagnose bacterial overgrowth as well as the Glucose Breath Test (GBT).
Glucose Breath Test (GBT)
Both humans and bacteria absorb glucose.
Glucose is absorbed within the first three feet of the small intestine, therefore if the bacterial gases of hydrogen and/or methane are produced during this test, it reflects an overgrowth in the proximal/upper end of the SI.
Glucose breath test can successfully and accurately diagnoses proximal overgrowth.
Glucose breath test disadvantage is that it cannot diagnose distal overgrowth, occurring in the latter 17 feet of the small intestine, which is thought to be more common.
The glucose breath test Is performed either at home with a take home kit or at a facility that has a breath testing machine.
It takes 1-3 hours in the morning after a 12 hour fast the night before and a special diet the day before.
There is no universally accepted standard among physicians at present for interpretation of results