Lab Test

Hydrogen and Methane, Breath

Hydrogen Breath Test, Methane Breath Test, Breath Test for Lactose Intolerance, Breath Test for Fructose Intolerance, Breath Test for Sucrose Intolerance, Breath Hydrogen, Breath Methane, Small Intestinal Bacterial Overgrowth, SIBO, Small Bowel Bacterial Overgrowth, SBBO

Test Codes

Antrim #13510, EPIC: LAB5865, SOFT: BRH2


Special Chemistry


  • For Outpatient collections, this test must be scheduled through the Beaumont Appointment Center at 800-328-8542.
  • Available sugar solutions include lactose, fructose, sucrose, and glucose. 
    Note that lactulose is not available.

Patient Preparation

Patients must arrive fasting and compliant with the instructions provided by their physician or by the Beaumont Appointment Center as follows:

  • For 4 weeks prior to testing, avoid antibiotics and bowel procedures such as colonoscopy that involve 'bowel cleaning.'
  • For 72 hours prior to testing, avoid:
    • Laxatives (e.g., magnesium compounds, senna)
    • Pro-motility medications (e.g., Reglan®, Metozolv®)
    • Anti-motility medications (e.g., Imodium®, Lomotil®)
  • For 24 hours prior to testing, avoid high-fiber foods and complex carbohydrates, onions, leeks, garlic, cabbage, and beans. Also avoid milk products and fruit juices.
  • On the day before testing, the evening meal should consist of cooked red meat or poultry or seafood, eggs, plain white rice or white bread.
  • Fast for 10-12 hours prior to testing. After the evening meal, do not eat anything or chew gum. You may drink water, but no other liquids, until 2 hours prior to testing.
  • The morning of testing, brush your teeth. Denture adhesive should be avoided.  Discontinue smoking until after the test is complete. Drink no liquids for 2 hours prior to testing. (If advised by your physician, medications may be taken with a small amount of water.) 
  • Bring a list of prescription and non-prescription medications and supplements you are taking.
  • The test takes approximately 3 hours to complete. During this time, you should not eat or drink anything, smoke, chew gum, sleep, or exercise.
  • Diarrhea and cramping may occur during testing.

Specimen Collection Criteria

Collect: 40 mL breath samples. Samples are collected before drinking the prescribed sugar solution and 30, 60, 90, 120, and 180 minutes thereafter.

  • Samples are collected in gas-tight 60 mL plastic syringes fitted with stopcocks, or transferred using a plastic syringe to approved breath storage bags.
  • Samples are collected using a nasal tube for adults or a mask for neonates. These allow the last few milliliters of an exhaled breath to be drawn into the syringe.
  • It is important that the patient inhale normally, but force as much air out of the lungs as possible.
  • Wait until the last part of the exhaled breath to draw about 5 mL of breath into the syringe. Repeat until 40-60 mL total is collected.
  • Close the stopcock and label with the time of collection and patient identification.
  • Dearborn Medical Park PSC: Transfer breath samples to designated breath storage bags labeled with time point and patient identifiers.  Send to Royal Oak Special Chemistry for analysis by the following day.

Rejection Criteria

Syringes or storage bags received with open stopcocks.

Inpatient Specimen Preparation

Deliver syringes to the Laboratory immediately.


Royal Oak Special Chemistry Laboratory


Royal Oak Medical Office Building PSC:
Monday, Wednesday, Thursday

Dearborn Medical Park PSC
Monday – Thursday

Results available by the next business day.

Reference Range

Hydrogen should increase by less than 20 ppm above the baseline collection. Methane should be less than 10 ppm at any time point.

Test Methodology

Solid-state sensors for hydrogen, methane, and carbon dioxide gases.


An increase greater than 20 ppm hydrogen above the baseline value in the 60, 90, 120, or 180 minute sample is compatible with enzyme deficiency and malabsorption. An increase greater than 10 ppm hydrogen in the 30 minute sample followed by a further increase at 90 or 120 minutes may also indicate bacterial overgrowth of the small bowel. An increase greater than 20 ppm at any time using glucose as the test substance is also consistent with bacterial overgrowth of the small bowel.

Note that if bacterial overgrowth is present in the small bowel, then lactose, fructose, or sucrose may also lead to elevations in breath hydrogen or methane. Thus, ruling out small bowel bacterial overgrowth should be considered prior to testing for carbohydrate malabsorption.

Methane greater than or equal to 10 ppm at any time point is considered a positive test and has been associated with constipation.

Clinical Utility

This test is used primarily to diagnose lactose malabsorption due to a deficiency of lactase enzyme in the intestine, but can be useful for sucrose and fructose malabsorption as well. It can also be helpful in diagnosing bacterial overgrowth of the small bowel.

CPT Codes



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