What is a Hydrogen Breath Test and Who Needs One?


A hydrogen breath test, also known as a lactose breath test, is generally used to diagnose one of three GI conditions: carbohydrate malabsorption, an overgrowth of intestinal bacteria, and abnormal digestive motility (the too-rapid or too-slow movement of food through the intestines). The test is performed by having the patient drink a solution, then measuring the levels of hydrogen in their breath at regular intervals as your GI tract digests the solution.

Normally, there should be very little hydrogen present when we exhale. When someone suffers from one of the three digestive disorders mentioned above, though, fermentation creates an excess of hydrogen in their GI tract. The hydrogen is then absorbed into the blood and exits the body as exhaled breath.

Carbohydrate Malabsorption

But you don’t have a digestive disorder, so you don’t need a hydrogen breath test, right? Think again. Carbohydrate malabsorption is the umbrella term for lactose intolerance. Lactose intolerance is generally thought of as the inability to digest dairy products, but it’s really only the sugar in dairy products (lactose) that affects people suffering from the condition. Fructose intolerance causes the same symptoms as lactose intolerance when foods that contain fructose are consumed, such as wheat, artichokes, onions, and pears.


Bacteria in Intestines

There are many types of bacteria found in the intestines, and having a variety of bacteria in your gut is best for digestion. If you have too much of a certain type of bacteria in your intestines, it can throw your whole body out of whack. Two examples of these conditions are Helicobacter Pylori infection and Bacterial Overgrowth Syndrome, also known as Small Intestine Bacterial Overgrowth (SIBO).

Carbohydrate malabsorption, an overabundance of intestinal bacteria, and abnormal GI motility all produce symptoms like bloating, abdominal pain, excess flatulence, diarrhea, and/or constipation. Many people aren’t aware that they may have these digestive conditions, but with a correct diagnosis, their symptoms can be effectively managed.

Hydrogen Breath Test Preparation

Hydrogen breath tests are non-invasive, inexpensive, and easy to use.

  • For 4 weeks before your test, don’t take antibiotics or undergo any procedures that require bowel cleansing.
  • On the day of your test, you shouldn’t use mouthwash, toothpaste, chewing gum, or tobacco products.
  • 8 hours before your hydrogen breath test, you will begin fasting to ensure that the test results are accurate.
  • You will be asked to blow air into a balloon-shaped bag, then drink a sweet-tasting solution.
  • You will breathe into the bag every 15-20 minutes for a period of up to 3 hours as you digest the solution, and the level of hydrogen in your breath will be measured to see if it rises.


You should be able to resume your normal activities after your hydrogen breath test is finished unless your gastroenterologist suggests otherwise. If you think you might benefit from a hydrogen breath test, contact Tulsa Endoscopy Center today!