Hydrogen breath test

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Hydrogen breath test
Purposediagnostic tool for carbohydrate malabsorption and small intestine bacterial overgrowth

A hydrogen breath test (or HBT) is used as a diagnostic tool for small intestine bacterial overgrowth and carbohydrate malabsorption, such as lactose, fructose, and sorbitol malabsorption. [1] [2]

Contents

The test is simple, non-invasive, and is performed after a short period of fasting (typically 8–12 hours). [3] Hydrogen breath tests are based on the fact that there is no source for hydrogen gas in humans other than bacterial metabolism of carbohydrates. [4] Even though the test is normally known as a "hydrogen" breath test, some physicians may also test for methane in addition to hydrogen. Many studies have shown that some patients (approximately 35% or more) do not produce hydrogen but actually produce methane. Some patients produce a combination of the two gases. [5] Other patients, who are known as "non-responders", don't produce any gas; it has not yet been determined whether they may actually produce another gas. In addition to hydrogen and methane, some facilities also utilize carbon dioxide (CO2) in the patient's breath to determine if the breath samples that are being analyzed are contaminated (either with room air or bronchial dead space air).

Physicians have expressed concern at the improper use and widespread overdiagnoses related to interpretation of these tests. [4] [6]

Conditions

Tests vary from country to country, so the following information is provided as a rough guide to typical uses of the hydrogen breath test:

Fructose malabsorption – the patient takes a base reading of hydrogen levels in their breath. The patient is then given 25-35g of fructose, and then required to take readings every 15, 30 or 60 minutes for three - five hours. The basis of the test is a failure to absorb the given sugar, which is then metabolized by bacteria that give off either hydrogen or methane. Therefore, the more gas that is produced, the less absorption has occurred. If the level of hydrogen rises above 20 ppm (parts per million) over the lowest preceding value within the test period, the patient is typically diagnosed as a fructose malabsorber. If the patient produces methane then the parts per million for the methane typically rises 12 ppm over the lowest preceding value to be considered positive. If the patient produces both hydrogen and methane then the values are typically added together and the mean of the numbers is used to determine positive results, usually 15 ppm over the lowest preceding value. A positive result may also be caused by small intestinal bacterial overgrowth, rather than fructose malabsorption. [7]

Lactose malabsorption – the patient takes a base reading of hydrogen levels in their breath. The patient is then given a small amount of pure lactose (typically 20 to 25 g), and then required to take readings every 15, 30 or 60 minutes for two to three hours. If the level of hydrogen rises above 20 ppm (parts per million) over the lowest preceding value within the test period, the patient is typically diagnosed as a lactose malabsorber. If the patient produces methane then the parts per million for the methane typically rises 12 ppm over the lowest preceding value to be considered positive. [8] [9] If the patient produces both hydrogen and methane then the values are typically added together and the mean of the numbers is used to determine positive results, usually 15 ppm over the lowest preceding value. [10] A positive result may also be caused by small intestinal bacterial overgrowth, rather than lactose malabsorption. [7]

Small intestinal bacterial overgrowth (SIBO) – the patient is either given a challenge dose of glucose, also known as dextrose (75–100 grams), or lactulose (10 grams). A baseline breath sample is collected, and then additional samples are collected at 15 minute or 20 minute intervals for 2 hours. Positive diagnosis for a lactulose SIBO breath test – typically positive if the patient produces approximately 20 ppm of hydrogen and/or methane within the first 60–90 minutes (indicates bacteria in the small intestine), followed by a much larger peak (colonic response). This is also known as a biphasic pattern. Lactulose is not absorbed by the digestive system and can help determine distal end bacterial overgrowth, which means the bacteria are lower in the small intestine.

Alternative test methods

The idea that a SIBO test should be several hours long and that distal overgrowth is important is not supported by the scientific literature. [11] [1] [4] [12] [13] [ failed verification ] [8] [ failed verification ] The optimal testing is 1 hour.[ dubious – discuss ] Small intestinal bacterial overgrowth (SIBO) occurs as a result of excessive numbers of bacteria inhabiting the proximal small intestine. Bacterial concentrations greater than 105 organisms per milliliter is diagnostic for SIBO. We know bacteria are colonizing the proximal and not the distal small intestine for several reasons. First, the gold standard method for detection of SIBO is jejunal aspirates. [11] [1] [4] [12] [13] [8] Intestinal fluid of the proximal intestine is sampled, not distal intestinal fluid. Secondly, the consequences of SIBO are the result of competition between bacteria and the human host for ingested nutrients in the intestine. Various functional consequences of bacterial infiltration cause enterocyte damage in the jejunum such as diminished disaccharidase activity, fat malabsorption, decreased amino acid transport and decreased vitamin B12 absorption. Thus, detection of proximal bacterial overgrowth is critical.

The SIBO breath test typically uses a 10 gram oral dose of lactulose for detection of proximal bacterial overgrowth. The best practice is to have breath samples collected at 20, 40, and 60 minutes after dosing. Since SIBO occurs in the proximal intestine, breath samples should be collected only within 1 hour after lactulose ingestion. This truly reflects proximal intestinal bacterial activity, not distal or colonic activity. The same argument is true if glucose is the substrate.

Lactulose is a carbohydrate that is not absorbed by humans. Lactulose is well known to measure oro-cecal transit time. [11] [1] [4] The mean oro-cecal transit time in normal healthy individuals is 70 to 90 minutes. [12] [13] [8] By 90 minutes, at least 50% of individuals would have delivered the lactulose dose to the colon. Approximately 90 to 95% of individuals have colonic bacteria that can metabolize lactulose to hydrogen or methane gas. Thus, any SIBO breath test that collects longer than 60 minutes may be measuring colonic activity. Diagnostic criteria of 20 ppm hydrogen and/or methane changes within 90 or 120 minutes will have higher positive rates of SIBO but this will reflect colonic activity not jejunal metabolism. A one-hour SIBO breath test avoids false positive results by collecting breath up to 60 minutes.

Positive diagnosis for a glucose SIBO breath test – glucose is absorbed by the digestive system so studies have shown it to be harder to diagnose distal end bacterial overgrowth since the glucose typically doesn't reach the colon before being absorbed. An increase of approximately 12 ppm or more in hydrogen and/or methane during the breath test could conclude bacterial overgrowth. Recent study indicates "The role of testing for SIBO in individuals with suspected IBS remains unclear." [14]

The excess hydrogen or methane is assumed to be typically caused by an overgrowth of otherwise normal intestinal bacteria. [11] [1] [4] [12] [13] [8]

Other breath tests that can be taken include: sucrose intolerance, d-xylose and sorbitol.

Related Research Articles

Flatulence, in humans, is the expulsion of gas from the intestines via the anus, commonly referred to as farting. "Flatus" is the medical word for gas generated in the stomach or bowels. A proportion of intestinal gas may be swallowed environmental air, and hence flatus is not entirely generated in the stomach or bowels. The scientific study of this area of medicine is termed flatology.

<span class="mw-page-title-main">Lactose intolerance</span> Inability to digest lactose

Lactose intolerance is caused by a lessened ability or a complete inability to digest lactose, a sugar found in dairy products. Humans vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain, bloating, diarrhea, flatulence, and nausea. These symptoms typically start thirty minutes to two hours after eating or drinking something containing lactose, with the severity typically depending on the amount consumed. Lactose intolerance does not cause damage to the gastrointestinal tract.

<span class="mw-page-title-main">Fructose malabsorption</span> Medical condition

Fructose malabsorption, formerly named dietary fructose intolerance (DFI), is a digestive disorder in which absorption of fructose is impaired by deficient fructose carriers in the small intestine's enterocytes. This results in an increased concentration of fructose. Intolerance to fructose was first identified and reported in 1956.

<span class="mw-page-title-main">Malabsorption</span> Medical condition

Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety of anaemias.

<span class="mw-page-title-main">Small intestinal bacterial overgrowth</span> Medical condition

Small intestinal bacterial overgrowth (SIBO), also termed bacterial overgrowth, or small bowel bacterial overgrowth syndrome (SBBOS), is a disorder of excessive bacterial growth in the small intestine. Unlike the colon, which is rich with bacteria, the small bowel usually has fewer than 100,000 organisms per millilitre. Patients with bacterial overgrowth typically develop symptoms which may include nausea, bloating, vomiting, diarrhea, malnutrition, weight loss and malabsorption, which is caused by a number of mechanisms.

The Schilling test was a medical investigation used for patients with vitamin B12 (cobalamin) deficiency. The purpose of the test was to determine how well a patient is able to absorb B12 from their intestinal tract. The test is now considered obsolete and is rarely performed, and is no longer available at many medical centers. It is named for Robert F. Schilling.

<span class="mw-page-title-main">Short bowel syndrome</span> Medical condition

Short bowel syndrome is a rare malabsorption disorder caused by a lack of functional small intestine. The primary symptom is diarrhea, which can result in dehydration, malnutrition, and weight loss. Other symptoms may include bloating, heartburn, feeling tired, lactose intolerance, and foul-smelling stool. Complications can include anemia and kidney stones.

<span class="mw-page-title-main">Lactulose</span> Treatment for constipation and hepatic encephalopathy

Lactulose is a non-absorbable sugar used in the treatment of constipation and hepatic encephalopathy. It is administered orally for constipation, and either orally or rectally for hepatic encephalopathy. It generally begins working after 8–12 hours, but may take up to 2 days to improve constipation.

Sucrase is a digestive enzyme that catalyzes the hydrolysis of sucrose to its subunits fructose and glucose. One form, sucrase-isomaltase, is secreted in the small intestine on the brush border. The sucrase enzyme invertase, which occurs more commonly in plants, also hydrolyzes sucrose but by a different mechanism.

Migrating motor complex, also known as migrating myoelectric complex, migratory motor complex, migratory myoelectric complex and MMC, is a pattern of electrical activity observed in the gastrointestinal tract in a regular cycle during fasting. MMC was discovered and characterized in fasting dogs in 1969 by Dr. Joseph H. Szurszewski at the Mayo Clinic. He also showed that this activity stops upon eating a meal, and suggested that it induces a motor activity that acts as a "interdigestive housekeeper" in the small intestine. These motor complexes trigger peristaltic waves, which facilitate transportation of indigestible substances such as bone, fiber, and foreign bodies from the stomach, through the small intestine, past the ileocecal sphincter, and into the colon. MMC activity varies widely across individuals and within an individual when measured on different days. The MMC occurs every 90–230 minutes during the interdigestive phase and is responsible for the rumbling experienced when hungry. It also serves to transport bacteria from the small intestine to the large intestine and to inhibit the migration of colonic bacteria into the terminal ileum; an impairment to the MMC typically results in small intestinal bacterial overgrowth.

<span class="mw-page-title-main">Blind loop syndrome</span> Medical condition

Blind loop syndrome, also known as stagnant loop syndrome, is a state that occurs when the normal bacterial flora of the small intestine proliferates to numbers that cause significant derangement to the normal physiological processes of digestion and absorption. In some cases of blind loop syndrome, overgrowth of pathogenic non-commensal bacteria has also been noted. It has long been understood that from birth, and throughout life, large amounts of bacteria reside symbiotically within animal gastrointestinal tracts such as the human gastrointestinal tract. The understanding of this gut flora has even led to novel treatments for bowel irregularity that utilize so called "probiotics" or good bacteria that aid in normal digestion. The problem of blind loop syndrome arises when the bacterial colonies residing in the upper gastrointestinal tract begin to grow out of control or are altered in their makeup thereby creating a burden on the normal physiological processes occurring in the small intestine. This results in problems, among others, of: vitamin B12 deficiency, fat malabsorption and steatorrhea, fat-soluble vitamin deficiencies and intestinal wall injury.

<span class="mw-page-title-main">Rifaximin</span> Antibiotic medication

Rifaximin, is a non-absorbable, broad spectrum antibiotic mainly used to treat travelers' diarrhea. It is based on the rifamycin antibiotics family. Since its approval in Italy in 1987, it has been licensed in over more than 30 countries for the treatment of a variety of gastrointestinal diseases like irritable bowel syndrome, and hepatic encephalopathy. It acts by inhibiting RNA synthesis in susceptible bacteria by binding to the RNA polymerase enzyme. This binding blocks translocation, which stops transcription. It is marketed under the brand name Xifaxan by Salix Pharmaceuticals.

<span class="mw-page-title-main">Sucrose intolerance</span> Medical condition

Sucrose intolerance or genetic sucrase-isomaltase deficiency (GSID) is the condition in which sucrase-isomaltase, an enzyme needed for proper metabolism of sucrose (sugar) and starch, is not produced or the enzyme produced is either partially functional or non-functional in the small intestine. All GSID patients lack fully functional sucrase, while the isomaltase activity can vary from minimal functionality to almost normal activity. The presence of residual isomaltase activity may explain why some GSID patients are better able to tolerate starch in their diet than others with GSID.

<span class="mw-page-title-main">Methylmalonic acid</span> Chemical compound

Methylmalonic acid (MMA) is a dicarboxylic acid that is a C-methylated derivative of malonic acid.

<span class="mw-page-title-main">Glucose-galactose malabsorption</span> Medical condition

Glucose-galactose malabsorption is a rare condition in which the cells lining the intestine cannot take in the sugars glucose and galactose, which prevents proper digestion of these molecules and larger molecules made from them.

An elemental diet is a diet that proposes the ingestion, or in more severe cases use of a gastric feeding tube or intravenous feeding, of liquid nutrients in an easily assimilated form. It is usually composed of amino acids, fats, sugars, vitamins, and minerals. This diet, however, lacks whole or partial protein due to its ability to cause an allergic reaction in some people.

Chronic diarrheaof infancy, also called toddler's diarrhea, is a common condition typically affecting up to 1.7 billion children between ages 6–30 months worldwide every year, usually resolving by age 4. According to the World Health Organization (WHO), diarrheal disease is the second greatest cause of death in children 5 years and younger. Diarrheal disease takes the lives of 525,000 or more children per year. Diarrhea is characterized as the condition of passing of three or more loose or watery bowel movements within a day sometimes with undigested food visible. Diarrhea is separated into three clinical categories; acute diarrhea may last multiple hours or days, acute bloody diarrhea, also known as dysentery, and finally, chronic or persistent diarrhea which lasts 2–4 weeks or more. There is normal growth with no evidence of malnutrition in the child experiencing persistent diarrhea. In chronic diarrhea there is no evidence of blood in the stool and there is no sign of infection. The condition may be related to irritable bowel syndrome. There are various tests that can be performed to rule out other causes of diarrhea that don't fall under the chronic criteria, including blood test, colonoscopy, and even genetic testing. Most acute or severe cases of diarrhea have treatment guidelines revolving around prescription or non prescription medications based on the cause, but the treatment protocols for chronic diarrhea focus on replenishing the body with lost fluids and electrolytes, because there typically isn't a treatable cause.

FODMAPs or fermentable oligosaccharides, disaccharides, monosaccharides, and polyols are short-chain carbohydrates that are poorly absorbed in the small intestine and ferment in the colon. They include short-chain oligosaccharide polymers of fructose (fructans) and galactooligosaccharides, disaccharides (lactose), monosaccharides (fructose), and sugar alcohols (polyols), such as sorbitol, mannitol, xylitol, and maltitol. Most FODMAPs are naturally present in food and the human diet, but the polyols may be added artificially in commercially prepared foods and beverages.

Intestinal bypass is a bariatric surgery performed on patients with morbid obesity to create an irreversible weight loss, when implementing harsh restrictions on the diets have failed. Jejunocolic anastomosis was firstly employed. Nonetheless, it led to some unexpected complications such as severe electrolyte imbalance and liver failure. It was then modified to jejunoileal techniques. Viewed as a novel form of treatment for obesity, many intestinal bypass operations were carried out in the 1960s and 1980s. Significant weight loss was observed in patients, but this surgery also resulted in several complications, for instance, nutritional deficiencies and metabolic problems. Due to the presence of surgical alternatives and anti-obesity medications, intestinal bypass is now rarely used.

A low-FODMAP diet is a person's global restriction of consumption of all fermentable carbohydrates (FODMAPs), recommended only for a short time. A low-FODMAP diet is recommended for managing patients with irritable bowel syndrome (IBS) and can reduce digestive symptoms of IBS including bloating and flatulence.

References

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  2. ↑ Rezaie, A (2017). "Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus". The American Journal of Gastroenterology. 112 (5): 775–784. doi:10.1038/ajg.2017.46. PMC   5418558 . PMID   28323273.
  3. ↑ Rana, Satya Vati; Malik, Aastha (2014-10-01). "Hydrogen Breath Tests in Gastrointestinal Diseases". Indian Journal of Clinical Biochemistry. 29 (4): 398–405. doi:10.1007/s12291-014-0426-4. ISSN   0970-1915. PMC   4175689 . PMID   25298621.
  4. 1 2 3 4 5 6 Simren, M.; Statzer, P-O. (2006). "Use and abuse of hydrogen breath tests". Gut. 55 (3): 297–303. doi:10.1136/gut.2005.075127. PMC   1856094 . PMID   16474100.
  5. ↑ de Lacy Costello BP, Ledochowski M, Ratcliffe NM (2013). "The importance of methane breath testing: a review". Journal of Breath Research (Review). 7 (2): 024001. Bibcode:2013JBR.....7b4001D. doi:10.1088/1752-7155/7/2/024001. PMID   23470880. S2CID   7675133.
  6. ↑ Massey, Benson T.; Wald, Arnold (10 October 2020). "Small Intestinal Bacterial Overgrowth Syndrome: A Guide for the Appropriate Use of Breath Testing". Digestive Diseases and Sciences. 66 (2): 338–347. doi:10.1007/s10620-020-06623-6. ISSN   1573-2568. PMID   33037967. S2CID   222234070 . Retrieved 24 October 2020.
  7. 1 2 Nucera G, Gabrielli M, Lupascu A, Lauritano EC, Santoliquido A, Cremonini F, Cammarota G, Tondi P, Pola P, Gasbarrini G, Gasbarrini A (June 2005). "Abnormal breath tests to lactose, fructose and sorbitol in irritable bowel syndrome may be explained by small intestinal bacterial overgrowth". Aliment Pharmacol Ther. 21 (11): 1391–5. doi:10.1111/j.1365-2036.2005.02493.x. PMID   15932370.
  8. 1 2 3 4 5 Ghoshal, U. C. (2011). "How to interpret hydrogen breath tests". J. Neurogastroenterol. Motil. 17 (3): 312–317. doi:10.5056/jnm.2011.17.3.312. PMC   3155069 . PMID   21860825.
  9. ↑ Deng, Yanyong; Misselwitz, Benjamin; Dai, Ning; Fox, Mark (2015-09-18). "Lactose Intolerance in Adults: Biological Mechanism and Dietary Management". Nutrients. 7 (9): 8020–8035. doi: 10.3390/nu7095380 . ISSN   2072-6643. PMC   4586575 . PMID   26393648.
  10. ↑ Däbritz, Jan; Mühlbauer, Michael; Domagk, Dirk; Voos, Nicole; Henneböhl, Geraldine; Siemer, Maria L; Foell, Dirk (2014-02-27). "Significance of hydrogen breath tests in children with suspected carbohydrate malabsorption". BMC Pediatrics. 14: 59. doi: 10.1186/1471-2431-14-59 . ISSN   1471-2431. PMC   3975941 . PMID   24575947.
  11. 1 2 3 4 Basilisco, G.; Risicato, R.; Bonazzi, P; Di Sario, A.; Portincasa, P. (2009). "H2-breath testing for evaluation of oro-caecal transit time". Aliment. Pharmacol. Ther. 29: 23–26. doi: 10.1111/j.1365-2036.2009.03951.x . PMID   19344474. S2CID   3905599.
  12. 1 2 3 4 Hirakawa, M.; Lida, M.; Kohrogi, N.; et al. (1988). "Hydrogen breath test assessment of orocecal transit time: Comparison with barium meal study". Am. J. Gastroenterol. 83 (12): 1361–1363. PMID   3195540.
  13. 1 2 3 4 Bond, J.H.; Levitt, M.D.; Prentiss, R. (1975). "Investigation of small bowel transit time in man utilizing pulmonary hydrogen (H2) measurements". J. Lab. Clin. Med. 85 (4): 546–555. PMID   1120927.
  14. ↑ Ford, A. C.; Spiegel, B. M.; Talley, N. J.; Moayyedi, P. (August 12, 2009). "Small intestinal bacterial overgrowth in irritable bowel syndrome: systematic review and meta-analysis". Clin. Gastroenterol. Hepatol. 7 (12): 1279–86. doi: 10.1016/j.cgh.2009.06.031 . PMID   19602448.
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