What is a hydrogen breath test?
A hydrogen breath test is used to either:
- detect the presence of an overgrowth of hydrogen-producing bacteria in your colon
- identify malabsorption and digestion issues, including lactose, sucrose, fructose and sorbitol intolerance
- identify problems with the passage of food through your bowel
The bacteria in your colon digest sugars and carbohydrates and use them as fuel. During this process, some of the sugars and carbohydrates are converted into gases, of which the most common is hydrogen. Some of this hydrogen is eliminated in your breath.
In a healthy digestive system, sugars and carbohydrates are predominantly digested and absorbed in the small intestine. Very little reaches the colon, so only small amounts of gas are produced by the bacteria there. However, when larger amounts of sugar or carbohydrate reach the colon or hydrogen-producing bacteria over-populate the colon, larger amounts of gas are formed.
You will be asked to breathe into a breath collection bag at the beginning of the test and then given a sugar solution to drink. You will then have to give samples of your breath every 15 minutes, usually over a few hours.
You will be asked not to eat or drink for several hours before the test and will have to follow a special diet a day or two before the test. Your physician may also advise you to avoid or stop taking certain medications for a period of time beforehand, including antibiotics.
Who needs a hydrogen breath test?
A hydrogen breath test may be recommended for you if your physician suspects that the gastrointestinal symptoms you are experiencing, such as bloating or abdominal pain, may be due to a carbohydrate or sugar intolerance, overly rapid passage of food through your bowel or bacterial overgrowth in your colon.
If you have postprandial hypoglycemia (low blood sugar after eating) of unknown cause, you are not a suitable candidate for a hydrogen breath test. Fructose must not be used in your test if hereditary fructose intolerance is suspected.