A breath test is a simple, painless procedure used to look for the presence of various digestive system conditions. The most common type is used to detect Helicobacter pylori (H. pylori) bacteria in the stomach or duodenum. This bacterium is known to cause conditions such as gastritis, duodenal ulcers and gastric ulcers. H. pylori infection is also associated with an increased risk of gastric cancer.

Other breath tests may be used to check for the presence of malabsorption, a condition in which a patient’s body fails to receive the nutrients it needs from foods that are eaten. Another type of breath test, called a breath alcohol test, is not related to digestion. This test, which is commonly used by law enforcement personnel to identify drunk drivers, measures the amount of alcohol on a person’s breath. 

Patients are urged to follow recommendations suggested by their physician when preparing for their breath test. These may include refraining from smoking cigarettes for a specified period of time or changes to dietary or medication regimens before the test is administered. Breath tests typically take place in a physician’s office.

During a breath test, patients breathe into a bag that is then sealed. This initial sample serves as a baseline against which a second sample is measured. Before the physician takes the second sample, the patient ingests a special solution. The nature of the solution differs depending on the type of test being performed.

Patients then breathe into a second bag, which also is sealed. The two samples are sent to a laboratory for analysis. A positive test indicates that the patient has the suspected condition and appropriate treatment will follow.