Information about our Hydrogen Breath Test for Physicians and other Health Care Providers

It Started with Hydrogen

Hydrogen breath tests (and more recently methane) has been used for decades in the diagnosis of digestive disorders of carbohydrate absorption, and more recently for small intestinal bacterial overgrowth (SIBO). They are based on the principle that when bacteria (in the intestine) digest carbohydrates (sugars, starches or vegetable fibers), they produce CO2 (as all other cells do) and hydrogen (H2) as well as methane (CH4).


Some bacteria also produce hydrogen sulfide (H2S) but the clinical significance of this is still under investigation, and measurement of this gas has not yet a firmly established role in diagnostics.

These gases get absorbed into the bloodstream and are exhaled, paving the way for end-expiratory analysis of breath samples for the diagnosis of associated disorders.

Hydrogen/Methane – The New Gold Standard

When either hydrogen or methane appear in the exhaled air, it is a sign that such carbohydrates have been exposed to bacterial metabolism.

Since absorption of glucose and fructose, as well as the disaccharides lactose and sucrose (after enzymatic splitting) occur in the small intestine, where bacteria are ordinarily not present in significant numbers, these absorptive processes do not lead to a significant rise in hydrogen or methane in breath samples of normal individuals. If, however, absorption is impaired, the unadulterated sugars reach the colon, are fermented and the hydrogen/methane production is significantly increased. The same holds true if there are abnormally high bacterial counts in the small bowel.


Some patients produce more hydrogen, some others more methane, in part because their bowel flora contains more methanogenic bacterial strains that convert hydrogen to methane. Measuring hydrogen alone (older breath-test analyzers) would therefore miss such patients, increasing the false negative test result rate.

Our Technology:

We utilize state-of-the-art gas chromatography analyzers (Quintron) that measure both hydrogen and methane concentrations very precisely and accurately. The analyzer also measures the CO2 concentration in the breath sample and applies a correction factor to the measured hydrogen and methane values to normalize these to a standardized CO2 concentration – and therefore adjust for potential variations of gas concentrations during sampling. This is necessary because during the breath cycle CO2 concentrations (and those of the other gases) vary, due to potential mixing with air in the deadspace/room air). In alveolar air the “normal” concentration of CO2 is around 5.5.% (equivalent to 40 mm Hg partial pressure) at sea level – and our machines are calibrated with this value to account and correct for improper sampling variations. Our analyzers are regularly calibrated with standardized gas mixtures to assure quality of analysis.

All our technicians are trained by a board certified gastroenterologist in the on-site sampling technique, performance of the analysis and in the interpretation of the test results. Results are also submitted to the gastroenterologist for review to assure correct interpretation. The customer receives the results from our company and can of course share them with a provider of their choice. Because of HIPAA regulations we will not regularly share results with providers directly, except if specific arrangements are made to comply with such regulation

Customers who choose to perform a hydrogen breath test at home, (and mail in their sample) will receive a complete sampling kit with detailed instructions, including a video explaining the sampling technique, and return-mail supplies. The samples are then processed in our facility using the AlveoVac system that assures accurate sample processing in the same analyzers used for our in-house samples.

Breath Testing Updates from our CMO, Dr. Martin Hahn

Lactose Intolerance

The most common application of these breath tests is for the diagnosis of Lactose Intolerance. This is a very common condition, not only in various ethnic groups, but also in older age, and associated with other illnesses (Celiac disease, Diabetes mellitus etc). A lactose hydrogen/methane breath test is a simple, non-invasive way to get a diagnosis.


More recently, SIBO has received a lot of attention – and is considered relatively common in patients after antibiotic therapy, after intestinal surgery, or as a result of medical therapies  for a variety of conditions (e.g. acid reflux treatment etc). It also seems to be associated with diseases that lead to gut motility problems or alter the intestinal environment, e.g. Scleroderma, Diabetes (especially with neuropathy, gastroparesis etc), Hypothyroidism, Inflammatory bowel disease, Diverticulosis and many others.

Other disorders

Other disorders that can be diagnosed by hydrogen/methane breath test are less well known, but are nevertheless rather common contributors to common GI-symptoms:

Examples are Fructose Malabsorption and Sucrose Intolerance.

>> Patients with these sensitivities may in fact be erroneously lumped into having a diagnosis of irritable bowel syndrome, rather than having a specific and treatable diagnosis of their specific carbohydrate-related disorder.

See below for a brief overview of these two disorders

Fructose Malabsorption (or non-hereditary Fructose Intolerance)

Fructose malabsorption is fairly common, affecting up to 1 in 3 people. It is just as common in people with a diagnosis of irritable bowel syndrome as in the rest of the population, and symptoms are quite similar but generally triggered by intake of fructose – containing foods. In some cases, fructose malabsorption may be caused by diseases which cause intestinal damage, such as celiac disease.

Fructose malabsorption is not to be confused with “hereditary fructose intolerance (HFI)” a rare, potentially fatal condition in which the liver enzymes that break up fructose are deficient.

Fructose malabsorption may cause gastrointestinal symptoms such as abdominal pain, bloating, flatulence and diarrhea.

Fructose is absorbed in the small intestine without help of digestive enzymes. Even in healthy persons, however, only about 25–50 g of fructose per sitting can be properly absorbed. People with fructose malabsorption absorb less than 25 g per sitting. Simultaneous ingestion of fructose and sorbitol seems to increase the malabsorption of fructose. Fructose that has not been adequately absorbed is fermented by intestinal bacteria producing hydrogen, methane and carbon dioxide, as well as short-chain-fatty-acids. This abnormal increase in hydrogen may be detectable with the hydrogen and methane breath tests with fructose as a substrate.

As a result of fructose malabsorption, rapid bacterial fermentation in the small intestine occurs, leading to altered gastrointestinal motility (e.g. diarrhea), the formation of mucosal biofilms, and a change in the intestinal flora. These effects are additive if other poorly absorbed carbohydrates are present, such as sorbitol. The clinical significance of these events depends upon the individual susceptibility to such changes. There is also evidence that fructose malabsorption can cause decreased Tryptophan, Folic Acid and Zinc levels in the blood.

Restricting dietary intake of free fructose and/or fructans (longer sugars containing fructose) may provide symptom relief in a high proportion of patients with such functional gut disorders.[12]

One has to be careful with the results of the Fructose Breath Test, because a negative result does not completely rule out that a trial of fructose restriction may help the patient (in other words, the sensitivity of the test is relatively low), while a positive result from such a hydrogen breath test is very specific that such a trial is useful.

Sucrose Intolerance

Sucrose (also called saccharose) is a two-sugar chain composed of Glucose and Fructose which are bonded together. A more familiar name is table, beet, or cane sugar. Sucrose Intolerance involves a deficiency in the enzyme Sucrase-Isomaltase which is supposed to break the bond between the glucose and fructose molecules. When such two-molecule sugars are consumed, they must be broken down into single-molecule sugars by enzymes in the intestines before they can be absorbed. Monosaccharides, or single sugar units, are then absorbed directly into the blood.

A genetic form of the enzyme deficiency is common in the indigenous populations of Canada and Alaska (3-10%), but less common in European (0.1%). Other, more common forms of deficiency are acquired and are frequently associated with irritable bowel syndrome, aging, or small intestinal disease (secondary sucrose intolerance). There are specific tests used to help determine if a person has sucrose intolerance. The most accurate test is the enzyme activity determination, which is done by biopsy of the small intestine. This is very accurate, but expensive, invasive, and complicated. Another test which can aid in the diagnosis is the sucrose breath test. It is easy to perform, and not costly — but it is less sensitive and specific than the enzyme activity test.

A deficiency of the enzyme may result in malabsorption of sugar, which can lead to potentially serious symptoms, including episodes of hypoglycemia (low blood sugar) — and as a result of that patients can experience palpitations and anxiety. Since Sucrase-Isomaltase is involved in the digestion of starches, some patients may not be able to absorb starches as well. It is important for those with sucrose intolerance to minimize sucrose consumption as much as possible. Enzyme supplements may be taken as a substitute for the missing enzyme.

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