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Jun 11, 2023

H. pylori breath test: Preparation, steps, and how it works

Helicobacter pylori (H. pylori) is a bacterium that can cause an infection in

Helicobacter pylori (H. pylori) is a bacterium that can cause an infection in the stomach. The H. pylori breath test is an accurate method of detecting the presence of the infection.

An H. pylori breath test measures the carbon dioxide (CO2) in an exhalation before and after drinking a solution containing a substance that the H. pylori bacterium breaks down.

Preparation for the breath test involves abstaining from certain medications for several weeks and fasting food and water a few hours before the test.

The test is safe during pregnancy and for children older than 3 years old.

In this article, we discuss how the H. pylori breath test works, its reliability, and who can take the test. We also look at the steps the test involves and what the results mean.

The H. pylori breath test measures an enzyme called urease, which is present in some microbes but not in human cells. H. pylori urease breaks down urea into CO2 and ammonia. It then uses ammonia to neutralize stomach acid and promote its colonization.

When urea breakdown occurs, CO2 enters the bloodstream and travels to the lungs, which release it in exhalations. The test measures a person's CO2 in their breath before and after ingesting a substance containing urea.

If the second breath sample has a higher than typical level of CO2, it is a sign of an H. pylori infection.

There are two types of tests available: 14C and 13C. The 14C screening involves a pill containing urea and a small amount of radiation equivalent to the natural environmental radiation a person receives within 24 hours.

In contrast, the 13C test contains urea without radiation.

Learn more about H. pylori.

An invasive testing method called an esophagogastroduodenoscopy (EGD) is the gold standard for diagnosing an H. pylori infection. Invasive means it involves injections, tubes, or scopes that enter the body.

However, due to its expense and invasiveness, it may not be the first method of choice for people younger than 60 years of age.

Noninvasive tests for H. pylori include breath, stool, and blood tests. A 2018 review of 101 studies found the H. pylori breath test is the most accurate noninvasive method of testing for the infection.

It is helpful in the initial diagnosis and the evaluation of treatment results.

Learn more about an EGD procedure.

Doctors recommend the H. pylori breath test for people:

If someone has symptoms typical of acid reflux, they do not need the test.

Additionally, doctors prefer the 13C test, or the nonradioactive version. Although the 14C is safe, 13C is a better choice for:

Before an H. pylori breath test, a person may need to stop taking certain medications. Some medications could cause false-negative results by reducing the urease activity of H. pylori. A false negative indicates someone does not have an infection when they do.

Medications to stop before the test may include:

Research also suggests that H2 blockers may cause false-negative results, so healthcare providers may recommend that a person stops taking such medication prior to a H. pylori breath test.

There is no need to stop taking antacids, but taking them on the day of the test is usually not recommended. A person should only take the medications that a doctor has approved on the day of the procedure.

Additionally, individuals should not discontinue prescribed medication without first checking with a healthcare professional.

A person must fast for 6 hours if they have the 14C test. For the 13C test, a person should follow their doctor's instructions regarding how long to abstain from food and beverages before the procedure.

A person will complete a typical 13C test by:

Following the test, a person may resume their everyday activities. People should have the test again 4–8 weeks after completing treatment for the H. pylori infection.

After the test, a person's breath samples go to a lab, where a technician evaluates them.

If the second CO2 level is higher than the baseline, it indicates the presence of urease from H. pylori, which is a positive result.

Conversely, if the two breath samples contain about the same level of CO2, it suggests the absence of urease, a negative result.

The results are often available within a few days.

Below are answers to some frequently asked questions:

H. pylori tests are available for home use. However, a person should check with their doctor before purchasing one.

The cost in a lab or facility may vary between $150 and $450. A home test may be less expensive.

An older 2014 study notes that people tolerate the test well. However, some anecdotal reports of side effects include nausea, tiredness, and stomach pains.

If someone experiences any troublesome effects, they should consult a doctor. To prevent an allergic reaction, they should also inform a healthcare professional of any allergies before undergoing the test.

The H. pylori breath test is noninvasive, making it safer and less expensive than endoscopic exams. Additionally, it is convenient and easy to repeat.

However, it may not provide accurate results for people with a history of stomach surgery or a recent history of bleeding from the upper gastrointestinal tract.

H. pylori is a bacterium with an enzyme called urease, which breaks down urea into CO2 and ammonia. The CO2 enters the lungs, and a person exhales it.

The H. pylori breath test measures the amount of CO2 in an exhalation before and after ingesting a urea-containing solution. If the CO2 is higher in the second exhalation, it accurately indicates the presence of an H. pylori infection.

Since some medications reduce urease activity, they can result in false negatives. Before the test, a person should tell a doctor about all the prescription and nonprescription drugs they take and follow instructions for temporarily discontinuing them.