Breath Hydrogen and Methane Testing Using GastroCH4ECK® and Gastro+™ Gastrolyzer®

Compared to the colon, the human small intestine usually contains fewer bacteria. Bacterial overgrowth can occur in the small intestine due to functional or structural disorders of the gastrointestinal tract, with colonic bacteria multiplying in the jejunum and ileum.

This condition is called small intestinal bacterial overgrowth or SIBO, and is characterized by diarrhea and steatorrhea, along with carbohydrate malabsorption and vitamin deficiencies. It is difficult to diagnose this syndrome accurately using blood tests.

Breath testing

In these cases, the basis for breath testing is that carbohydrates can be broken down by bacteria in the intestine to generate hydrogen and methane. Bacterial fermentation of carbohydrate in the gut is the only source of hydrogen and methane gases in in alveolar air and therefore, the amount of hydrogen and methane in breath samples is calculated to investigate the passage of carbohydrates via the gut and the existence of pathogenic bacteria in the gastro-intestinal lumen.

Breath hydrogen and methane testing offers a non-invasive, safe alternative solution to procedures such as biopsy to assess malabsorption, constipation, diarrhea, and bloating. The 1970s and 2006 research revealed that nearly 35% of healthy adult subjects are methane producers. Other study results also showed that 34% of patients having lactose intolerance showed a rise of methane percentage of more than 100%, but also a negative hydrogen breath test.

Breath testing to help in SIBO diagnosis may also offer a framework for the study of irritable bowel syndrome (IBS). Recent work has shown that methane production in the lactulose breath test on IBS subjects is related to constipation. It is also observed that methane slows down the passage of food via the intestinal tract.

Suggested testing protocol

With the exception of water, patients must fast 12 hours before the test, avoiding alcohol and food. Additionally, patients must avoid eating slowly digesting foods such as beans the day prior to the test. It is necessary to take a baseline breath test before administering any substrate:



Test frequency (minutes)



25g of Lactose in 200ml of water

0, 60, 120, 180



25g of Lactose in 250ml of water

0, 15, 30, 60, 90, 120



10g of Lactulose in 200ml of water

0, 20, 40, 60, 80, 100, 120, 140, 160, 180



25g of Fructose in 250ml of water

0, 60, 120, 180



25g of Fructose in 250ml of water

0, 15, 30, 60, 90, 120



12.5g of Sorbitol in 250ml of water

0, 15, 30, 60, 90, 120



25g of Xylitol in 250ml of water

0, 15, 30, 60, 90, 120



50g of glucose in 250ml of water

0, 15, 30, 45, 60



Comprehensive hydrogen interpretation of readings, indications, symptoms, and interferences are described in ‘Hydrogen Breath Tests’ by Professor Maximilian Ledochowski, which is provided along with both the GastroCH4ECK® and Gastro+™ Gastrolyzer®.

Guideline interpretation is listed in the following table, again if there is more than one opinion available, this has been applied and referenced, other opinions may be used:


Positive Interpretation

Lactose3, 9

H2 ≥20ppm CH4 ≥12ppm compared to basal sample


H2 & CH4 >20ppm compared to basal sample within 90 minutes of lactulose ingestion

Lactulose3 SIBO*

a) Early increase of at least 20ppm for the sum of the two gases

b) Increase ≥20ppm corresponding to the appearance of lactulose in the colon

Lactulose3 IITT**

Fast ≥20ppm peak is detected at 60 minutes

Normal ≥20ppm peak is detected at 80 minutes

Slow ≥20ppm peak is detected 100 minutes or later


H2 ≥20ppm CH4 ≥12ppm compared to basal sample


H2 ≥20ppm compared to basal sample


H2 ≥20ppm compared to basal sample


H2 ≥10ppm CH4 ≥10ppm compared with basal sample

*SIBO = Small Intestinal Bacterial Overgrowth

**IITT = Impaired Intestinal Transit Time


  1. Drossman DA. The functional gastrointestinal disorders and the Rome III process. In: Drossman DA, Corazziari E, Delvaux M, Spiller R, Talley NJ, Thompson WG, et al., eds. Rome III: The Functional Gastrointestinal Disorders. 3rd ed. McLean, VA: Degnon Associates; 2006:1-30.
  2. Drossman DA. The functional gastrointestinal disorders and the Rome III process. Gastroenterology. 2006;130:1377-1390.
  3. Biolab Medical Unit; Nutritional and Environmental Medicine; London England. Breath Hydrogen and Methane February 2012. Available at
  4. Levitt MD, Furne JK, Kuskowski M, Ruddy J. Stability of human methanogenic flora over 35 years and a review of insights obtained from breath methane measurements. Clin Gastorenterolo Hepatol. 2006;2:123-129
  5. Corazza GR, Benati G, Strocchi A, Malservisi S, Gasbarrini G. The possible role of breath methane measurement in detecting carbohydrate malabsorption. J Lab Clin Med. 1994;124:695-700.
  6. Kumar D, Wingate DL. The irritable bowel syndrome: a paroxysmal motor disorder. Lancet 1985; 2: 973-977.
  7. Chatterjee S, Park S, Low K, Kong Y, Pimentel M. The degree of breath methane production in IBS correlates with the severity of constipation. Am J Gastroenterol 2007;102:1-5.
  8. Bratten JR, Jones MP. Small intestinal motility. Curr Opin Gastroenterol. 2007;23:127-133
  9. Ledochowski M. Ledochowski E. Hydrogen Breath Tests 2008; Available from Bedfont Scientific Ltd
  10. Pimental M. et al Methane Production During Lactulose Breath Test is Associated with Gastrointestinal Disease Presentation. Digestive Diseases and Sciences, Vol

About Bedfont ScientificBedfont® Scientific Ltd

Bedfont® Scientific has specialised in the design and manufacture of exhaled breath and gas monitoring instruments since 1976.

For medical gas monitoring, their Medi-Gas Check medical pipeline testing range verifies not only the quantity but also quality of gas administered to patients.

Bedfont's breath analysers include carbon monoxide (CO) monitors such as the Smokerlyzer®, used for smoking cessation, and the ToxCO®, used by emergency services, to diagnose CO poisoning.

The NObreath® FeNO monitor provides accurate analysis of airway inflammation for the control of asthma, and the Gastrolyzer® range aids in the detection of gastrointestinal disorders and food intolerances. Quick and non-invasive, breath analysis is the new blood test.

Sponsored Content Policy: publishes articles and related content that may be derived from sources where we have existing commercial relationships, provided such content adds value to the core editorial ethos of News-Medical.Net which is to educate and inform site visitors interested in medical research, science, medical devices and treatments.

Last updated: Feb 18, 2021 at 10:23 AM


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