Table of ContentsView AllTable of ContentsHow It WorksTypesPreparationProcedureInterpreting ResultsFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
How It Works
Types
Preparation
Procedure
Interpreting Results
Frequently Asked Questions
A hydrogen breath test is used to measure the amount of hydrogen gas in a person’s breath. It can be used as part of diagnosing some digestive conditions, especiallysmall intestinal bacterial overgrowth (SIBO), carbohydrate malabsorption (including fructose, sucrose, andlactose intolerance), and if food is moving too slowly through thesmall intestine.
This type of test was first described in 1975, but it has not always been widely used. People may be given the option of taking this test if they have symptoms ofabdominal pain,bloating, gas,constipation, ordiarrheathat are going on for a long time (chronic).
This article will discuss why a hydrogen breath test might be used, how the test is done, and what the results might mean.
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How Hydrogen Breath Tests Work
Types of Hydrogen Breath Tests
There are a few different types of hydrogen breath tests. You will be given a solution to drink that contains a specific type of sugar.
Lactose Breath Test
Lactose is the sugar that’s found in milk. Not being able to digest milk sugar is a common condition called lactose intolerance. In this test, you will drink a solution that contains lactose.
Fructose Breath Test
Fructose is a type of sugar that is found in honey, vegetables, fruits, and grains. Not being able todigest fructose fullyis common. In this form of the test, patients are given a drink that contains fructose.
SIBO Breath Test
The overgrowth of bacteria in the small intestine can result in the production of too much hydrogen. For this test, you will drink a solution containing glucose or lactulose.
The hydrogen breath test is noninvasive and inexpensive. However, it will require some preparation. The healthcare provider will give you specific steps to follow and advise you on which medications to avoid and what dietary changes you should make.
In the month (four weeks) before having a hydrogen breath test, you should stop taking:
In the one or two weeks before the test, you should avoid taking:
In the two days before the test, you will be asked to eat a diet that’s low in carbohydrates and dairy products. This includes avoiding foods with wheat, beans, milk products, foods with high fructose corn syrup, natural and artificial sweeteners, and fruits and vegetables containing high fructose levels.
It isn’t easy or simple to know exactly which foods to avoid and which are allowed, so your healthcare provider should give you a list. If a list isn’t provided, you should ask for one to ensure you’re following the right diet.
On the day of the test, you will also be asked to:
The procedure is fairly straightforward but will take two to three hours. The first step is to get a baseline breath sample. You will breathe into a bag to collect the sample.
Next, you will drink the solution that contains a type of sugar. You will then be asked to breathe into a plastic bag every 15 or 20 minutes. For children, this interval might be every 30 minutes.
Each sample of breath taken will be measured for its hydrogen content. The measurement is done with a device called a gas chromatograph.
The level of hydrogen in the breath is measured in parts per million (ppm). The test samples will be compared against the initial sample taken before the test began.
When the amount of hydrogen in a test sample is higher than the first sample, it may indicate a problem with absorption in the small intestine. A rise of 10 parts per million (ppm) or more might mean a glucose or fructose intolerance. A 20 ppm or more rise might mean that lactose intolerance or SIBO is present.
Other gases measured
The healthcare provider who ordered the test will help in explaining what the results might mean. If the results indicate a condition that needs treatment, you may be given a referral to a specialist.
There are, however, some problems that can occur with these test results, which can result in a false positive or a false negative.
A false negative is also possible. This is when there is actually a condition present, but the test doesn’t indicate the high level of hydrogen. This happens in about 10% of tests.
It’s worth discussing the potential for false-positive and false-negative results with a healthcare provider. In some cases, more tests may be needed.
Summary
A Word From Verywell
The hydrogen breath test is helpful in finding the cause of digestive symptoms. Lactose intolerance has been recognized for a long time, but not being able to digest sugars such as fructose is not as well known. The hydrogen breath test can detect this.
SIBO is also increasingly understood and diagnosed, especially in the setting of other digestive conditions, such asirritable bowel syndrome (IBS).The hydrogen breath test may not be the only tool to determine the cause of symptoms, but it is relatively straightforward and is increasingly available.
Frequently Asked QuestionsYes, the hydrogen breath test is considered to be pretty accurate. However, it’s important that all the instructions about diet and medications are followed in the weeks and days leading up to the test. Not following them might make the test inaccurate.Yes, it will be necessary to fast before this test. It’s important to get results from the drink that’s given and not other foods that are eaten or drunk.The time leading up to the test can be several weeks while diet and medications are adjusted. The test itself should take two to three hours to complete.
Yes, the hydrogen breath test is considered to be pretty accurate. However, it’s important that all the instructions about diet and medications are followed in the weeks and days leading up to the test. Not following them might make the test inaccurate.
Yes, it will be necessary to fast before this test. It’s important to get results from the drink that’s given and not other foods that are eaten or drunk.
The time leading up to the test can be several weeks while diet and medications are adjusted. The test itself should take two to three hours to complete.
4 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Robles L, Priefer R.Lactose intolerance: what your breath can tell you.Diagnostics (Basel).2020;10:412. doi:10.3390/diagnostics10060412.Rezaie A, Buresi M, Lembo A, et al.Hydrogen and methane-based breath testing in gastrointestinal disorders: The North American consensus.Am J Gastroenterol.2017;112:775-784. doi:10.1038/ajg.2017.46.Hammer HF, Fox MR, Keller J, et al.European guideline on indications, performance, and clinical impact of hydrogen and methane breath tests in adult and pediatric patients: European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Neurogastroenterology and Motility, and European Society for Paediatric Gastroenterology Hepatology and Nutrition consensus.United European Gastroenterol J. 2022;10(1):15-40. doi:10.1002/ueg2.12133Takakura W, Pimentel M.Small intestinal bacterial overgrowth and irritable bowel syndrome - an update.Front Psychiatry. 2020;11:664. doi:10.3389/fpsyt.2020.00664.Additional ReadingNewcomer AD, McGill DB, Thomas PJ, Hofmann AF.Prospective comparison of indirect methods for detecting lactase deficiency.N Engl J Med.1975;293:1232–1236. doi: 10.1056/NEJM197512112932405.
4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Robles L, Priefer R.Lactose intolerance: what your breath can tell you.Diagnostics (Basel).2020;10:412. doi:10.3390/diagnostics10060412.Rezaie A, Buresi M, Lembo A, et al.Hydrogen and methane-based breath testing in gastrointestinal disorders: The North American consensus.Am J Gastroenterol.2017;112:775-784. doi:10.1038/ajg.2017.46.Hammer HF, Fox MR, Keller J, et al.European guideline on indications, performance, and clinical impact of hydrogen and methane breath tests in adult and pediatric patients: European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Neurogastroenterology and Motility, and European Society for Paediatric Gastroenterology Hepatology and Nutrition consensus.United European Gastroenterol J. 2022;10(1):15-40. doi:10.1002/ueg2.12133Takakura W, Pimentel M.Small intestinal bacterial overgrowth and irritable bowel syndrome - an update.Front Psychiatry. 2020;11:664. doi:10.3389/fpsyt.2020.00664.Additional ReadingNewcomer AD, McGill DB, Thomas PJ, Hofmann AF.Prospective comparison of indirect methods for detecting lactase deficiency.N Engl J Med.1975;293:1232–1236. doi: 10.1056/NEJM197512112932405.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Robles L, Priefer R.Lactose intolerance: what your breath can tell you.Diagnostics (Basel).2020;10:412. doi:10.3390/diagnostics10060412.Rezaie A, Buresi M, Lembo A, et al.Hydrogen and methane-based breath testing in gastrointestinal disorders: The North American consensus.Am J Gastroenterol.2017;112:775-784. doi:10.1038/ajg.2017.46.Hammer HF, Fox MR, Keller J, et al.European guideline on indications, performance, and clinical impact of hydrogen and methane breath tests in adult and pediatric patients: European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Neurogastroenterology and Motility, and European Society for Paediatric Gastroenterology Hepatology and Nutrition consensus.United European Gastroenterol J. 2022;10(1):15-40. doi:10.1002/ueg2.12133Takakura W, Pimentel M.Small intestinal bacterial overgrowth and irritable bowel syndrome - an update.Front Psychiatry. 2020;11:664. doi:10.3389/fpsyt.2020.00664.
Robles L, Priefer R.Lactose intolerance: what your breath can tell you.Diagnostics (Basel).2020;10:412. doi:10.3390/diagnostics10060412.
Rezaie A, Buresi M, Lembo A, et al.Hydrogen and methane-based breath testing in gastrointestinal disorders: The North American consensus.Am J Gastroenterol.2017;112:775-784. doi:10.1038/ajg.2017.46.
Hammer HF, Fox MR, Keller J, et al.European guideline on indications, performance, and clinical impact of hydrogen and methane breath tests in adult and pediatric patients: European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Neurogastroenterology and Motility, and European Society for Paediatric Gastroenterology Hepatology and Nutrition consensus.United European Gastroenterol J. 2022;10(1):15-40. doi:10.1002/ueg2.12133
Takakura W, Pimentel M.Small intestinal bacterial overgrowth and irritable bowel syndrome - an update.Front Psychiatry. 2020;11:664. doi:10.3389/fpsyt.2020.00664.
Newcomer AD, McGill DB, Thomas PJ, Hofmann AF.Prospective comparison of indirect methods for detecting lactase deficiency.N Engl J Med.1975;293:1232–1236. doi: 10.1056/NEJM197512112932405.
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