H. pylori breath test: Preparation, steps, and how it works Health ConditionsHealth ConditionsAlzheimer's & DementiaAnxietyArthritisAsthma & AllergiesBreast CancerCancerCardiovascular HealthCOVID-19Dermatology & SkincareDiabetesEnvironment & SustainabilityExercise & FitnessEye HealthHeadache & MigraineHealth EquityHIV & AIDSHuman BiologyInflammatory Bowel DiseaseLeukemiaLGBTQIA+Men's HealthMental HealthMultiple Sclerosis (MS)NutritionParkinson's DiseasePsoriasisSexual HealthWomen's HealthDiscoverNewsLatest NewsOriginal SeriesMedical MythsHonest NutritionThrough My EyesNew Normal HealthPodcastsHow to understand chronic painWhat is behind vaccine hesitancy?The amazing story of hepatitis C, from discovery to cureNew directions in dementia researchCan psychedelics rewire a depressed, anxious brain?Why climate change matters for human healthToolsGeneral HealthDrugs A-ZHealth HubsHealth ToolsBMI Calculators and ChartsBlood Pressure Chart: Ranges and GuideBreast Cancer: Self-Examination GuideSleep CalculatorHealth ProductsAffordable Therapy OptionsBlood Pressure MonitorsDiabetic SuppliesFitness TrackersHome GymsGreen Cleaning ProductsHow to Shop for CBDQuizzesRA Myths vs FactsType 2 Diabetes: Managing Blood SugarAnkylosing Spondylitis Pain: Fact or FictionConnectAbout Medical News TodayWho We AreOur Editorial ProcessContent IntegrityConscious LanguageNewslettersSign UpFollow UsMedical News TodayHealth ConditionsDiscoverToolsConnectSubscribe What to know about the H pylori breath testMedically reviewed by Cynthia Taylor Chavoustie, MPAS, PA-C — By Mary West on September 29, 2022Helicobacter 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. What is it Share on PinterestStephen Barnes/AlamyThe 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. Is it reliable 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. Who can take this test Doctors recommend the H. pylori breath test for people:experiencing pain or discomfort in the upper abdomenwith associated conditions, such as stomach cancer or a peptic ulceron long-term aspirin therapy or beginning long-term nonsteroidal anti-inflammatory drug therapy 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:people of childbearing agethose who are pregnantchildren older than 3 years old Preparation 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:bismuth compounds for at least 4 weeksantibiotics for at least 4 weeksproton pump inhibitors for at least 2 weeks 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. The test Step by step A person will complete a typical 13C test by:breathing into a balloon-like bag for an exhaled CO2 baseline leveldrinking a citric acid mixture that contains ureabreathing again into a balloon-like bag after 15 minutes for another CO2 measurement to compare to the baseline level 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. Results 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. Frequently asked questions Below are answers to some frequently asked questions: Can I do the test at home H. pylori tests are available for home use. However, a person should check with their doctor before purchasing one. How much does it cost The cost in a lab or facility may vary between $150 and $450. A home test may be less expensive. Are there any side effects 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. What are the advantages and disadvantages 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. Summary 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. Last medically reviewed on September 29, 2022GastroIntestinal / GastroenterologyInfectious Diseases / Bacteria / Viruses 6 sourcescollapsedMedical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.Best, L. M. J., et al. (2018). Noninvasive diagnostic tests for Helicobacter pylori infection.https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD012080.pub2/fullHelicobacter pylori (H. Pylori) tests. (2021).https://medlineplus.gov/lab-tests/helicobacter-pylori-h-pylori-testsLopes, A. I., et al. (2014). Helicobacter pylori infection - recent developments in diagnosis.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4110561Mounsey, A., et al. (2019). Noninvasive Diagnostic Tests for Helicobacter pylori Infection.https://www.aafp.org/pubs/afp/issues/2019/0701/p16.htmlSankararaman, S., et al. (2021). Urea breath test.https://www.ncbi.nlm.nih.gov/books/NBK542286Savarino, V., et al. (2001). Negative effect of ranitidine on the results of urea breath test for the diagnosis of helicobacter pylori [Abstract].https://journals.lww.com/ajg/Abstract/2001/02000/Negative_Effect_of_Ranitidine_on_The_Results_of.19.aspxFEEDBACK:Medically reviewed by Cynthia Taylor Chavoustie, MPAS, PA-C — By Mary West on September 29, 2022 Latest newsWhat sets 'SuperAgers' apart? Their unusually large neuronsOmega-3 may provide a brain boost for people in midlifeSeasonal affective disorder (SAD): How to beat it this fall and winterCDC: Monkeypox in the US 'unlikely to be eliminated in the near future'Why are more women prone to Alzheimer's? New clues arise Related CoverageWhat are the best natural H. pylori treatments?Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT The bacteria H. pylori can cause a range of gastrointestinal issues, including gastritis. Infection may even lead to gastric cancer. Fortunately…READ MORE11 foods that are easy to digestMedically reviewed by Natalie Butler, R.D., L.D. Some health conditions, such as acid reflux, can make it hard for people to digest food. What are the best foods to eat when this happens? Find out…READ MORETips for better digestion - how long does it take?Medically reviewed by Natalie Butler, R.D., L.D. What happens inside the body after a person eats dictate how they put on weight and how long it takes to process nutrients. Find out the typical…READ MOREWhat are gram positive bacteria? When bacteria retain the crystal violet dye during the Gram stain test, they are called Gram-positive bacteria. Learn more here. READ MOREWhat is the difference between Gram-positive and Gram-negative bacteria? Gram-positive and gram-negative bacteria are distinct types of bacteria. Learn more here.READ MORE