SIBO (Small Intestinal Bacterial Overgrowth) – 2 Hour (Breath)


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Convenient Delivery:

  • Direct to Your Home: PW Therapy partners with top laboratories to deliver test kits right to your door after you make a purchase. We handle all outgoing postage costs.
  • Delivery Timeline: Expect your kit within five working days, although this may shift due to external circumstances beyond our control. 

Simple Test Return Procedure:

  • Return Options: Once you’ve completed the test, send it back to the lab using the pre-provided courier slip or choose to use Royal Mail services.
  • Cost-Effective Return: Sending your test back to us is economical, with postage to the labs costing only £5-10.

Prompt Results Processing:

  • Results in 48 Hours: After PW Therapy receives your test results, we commit to processing and sending them to you within 48 hours.
  • Expert Consultations Available: For a detailed understanding of your results and tailored advice on next steps, please book a consultation with our specialist team.


Small Intestinal Bacterial Overgrowth (SIBO) is a common condition associated with many symptoms and diseases including:

  • Bloating (especially after meals)
  • Gas
  • Diarrhoea
  • Constipation
  • Abdominal pain
  • Indigestion
  • Irritable Bowel Syndrome (IBS)
  • Inflammatory Bowel Disease (IBD)
  • Coeliac Disease
  • Diabetes
  • Fibromyalgia
  • Rosacea
  • Parkinson’s Disease
  • Obesity

Breath testing is a unique way of determining if you have too many bacteria growing in your small intestine. Treatment may involve eliminating the overgrowth with antibiotics, herbal supplements, and/or a specialised diet.

Testing involves a preparation diet, overnight fasting, and a specific breath technique with the collection materials. We have many resources to help make your testing experience a success. Review the Test Preparation tab to learn more about the collection process.


Preparing for this Test

Certain medications, supplements, and/or foods may impact test results. Please note that the reference ranges were established based on patients who were taking no medications or supplements. In some instances it is unknown what potential impact a medication may have on test results.

Genova never recommends that patients discontinue medically necessary medications or supplements in order to complete testing.

There may be times when a patient may stay on a medication or dietary supplement during testing in order to evaluate its effectiveness. The recommendation to discontinue any substance is intended to establish a baseline finding. While there are no rigid rules on time frames for discontinuing supplements to establish a baseline, some clinicians choose to discontinue 4 days prior to testing. If you choose to discontinue a medication, a good rule of thumb is to take the biological half-life of the drug times 5 to allow for ‘clearance’ before testing. With certain medications, the drug itself may have cleared the body, but the effect of the medication may be longer lasting. Below you will find a list detailing the potential interference or influence of certain substances on the biomarkers.


Common But Preventable Collection Mistakes

To prevent sample recollection, follow the instructions in your collection pack and avoid the common causes for rejected samples described below.

Putting the tube on the needle before breathing into the collection device.
  • Reason: Room air has contaminated the sample.
  • Correct collection method: Make sure you are breathing out before you puncture the tube with the collection device needle. Once you put the tube on mid-exhalation, hold the tube in place for two seconds and then remove it before your breath is complete.
Taking a very big inhalation before the sample.
  • Reason: Room air has contaminated the sample.
  • Correct collection method: Make sure to take a normal breath in, as you would in normal breathing.
Putting the tube on the needle at the beginning of the exhalation instead of mid-exhalation.
  • Reason: If you put the tube on early, the air in the tube will be air from your trachea, but we want to wait until mid-exhalation to capture the air from your lungs.
  • Correct collection method: Put the tube on mid-exhalation, hold the tube in place for two seconds, and then remove it before your breath is complete.
Puncturing the tube more than once.
  • Reason: This may cause the sample to leak out of the tube before it can be analyzed.
  • Correct collection method: Only puncture the tube once. If a tube is mistakenly punctured twice, please still submit the tube for analysis as the sample may still be valid



Collection Pack Instruction Recommended Timeframe to Discontinue Possible Impact on Results
Colonoscopy or barium enema 4 weeks May alter bacteria levels; 4 weeks is thought to be enough time for the intestinal flora to reestablish a baseline and for the GI tract to normalize after these procedures.
Antibiotics The North American SIBO Consensus group recommends discontinuing antibiotics 4 weeks prior to testing. This may be beneficial for initial testing.1 Clinicians may choose to test shortly after cessation of antibiotic therapy to confirm eradication.
Antifungals, herbal/natural antimicrobial products 2-4 weeks Can alter/influence bacterial composition.
Pepto-Bismol Generally given as part of H.pylori treatment, Pepto-Bismol is also known to impact other bacteria.2
Laxatives, stool softeners, stool bulking agents (Ex-Lax, Colace, Metamucil, Fibercon) 7 days The North American SIBO Consensus group recommends discontinuing promotility drugs and laxatives 7 days prior to testing only if tolerated by the patient. A 4-week gap had previously been recommended, but the consensus group agreed that this time frame may not be practical for discontinuation.1 These substances can result in faster transit time and an earlier delivery of the lactulose substrate to the colon, resulting in a false-positive finding. If the use of laxatives normalizes transit time, continuing the medication may not be an issue. Fiber-containing agents may feed large intestine bacteria resulting in a false-positive finding. In patients who are severely constipated, it may be difficult to be off of this support for 7 days, so some clinicians may choose to discontinue at least 2-4 days prior. Other ways to help support patients with constipation include exercise, appropriate hydration, and trying to avoid foods that the patient knows aggravates constipation.
Antacids containing aluminum or magnesium hydroxide (For collections based in the United States, examples include Maalox liquid, Equate, Milk of Magnesia, Rolaids, Mylanta) Certain antacids can influence transit time, which may influence test results.
Diet must be limited; the only ALLOWED foods include baked or broiled chicken, fish or turkey (salt and pepper only), white bread (only), plain steamed white rice, eggs, clear chicken or beef broth (no vegetable pieces). Allowed beverages include water, plain coffee and tea (no sugar/artificial sweeteners or cream). 24 hours before High fiber foods or foods containing fermentable carbohydrates can be acted on by the large intestine bacteria. In order to ensure the test does not result in false positives or an elevated baseline from large intestine bacteria, the recommended diet must be followed. Clinicians may extend the diet to 48 hours for patients who are constipated.
Probiotics (i.e. acidophilus) Probiotics have been shown to affect hydrogen levels on breath testing; the North American SIBO Consensus group did not reach a firm position statement on stopping probiotics prior to breath testing.1
Fast from food, only water is allowed 12 hours before Fasting prior to breath collection is important to ensure that the small intestine is clear of any food. A false positive or elevated baseline may result from not adhering to this instruction.
No non-essential medications or supplements, gum, candy or mouthwash May result in elevated breath gas levels and possibly false-positive results.
No smoking (including secondhand), sleeping, or vigorous exercise; this includes waiting at least 1 hour after waking for the day 1 hour before and during Results in elevated breath gas levels and possibly false-positive results.1
Toothpaste Toothpaste may contain fermentable ingredients for oral bacteria, resulting in a false-positive test result.


We do not suggest collecting during an acute gastrointestinal infectious illness. Transit time and intestinal flora may be altered, which can impact test results.


Patients with Lactose Intolerance or Allergy to Lactulose

This test uses lactulose as its testing agent, and is not recommend for individuals who have had allergic reactions to lactulose, or are on a galactose/lactose-restricted diet. The full dose of lactulose for this test is 10 grams. Allergic reactions to lactulose, which are IgE-mediated and may present with such symptoms as hives, difficulty breathing, or swelling, are quite rare but can be serious. More commonly individuals may have a food sensitivity, which involves a milder, delayed reaction, which can include various symptoms including congestion, gastrointestinal discomfort, and eczema. It is also worth noting that the lactose intolerance precaution refers to those individuals who may simply have symptoms of bloating or discomfort after consuming lactose due to lactase enzyme deficiency. Though not likely dangerous, GI distress is possible with exposure to this drink in these individuals. Lactose intolerance will not interfere with test results. The healthcare provider will need to decide whether to run the test in light of a possible symptomatic response.


Patients with Diabetes

The test uses lactulose as its testing agent, and should be used with caution in diabetics, as it has the potential to raise blood sugar. Per the VistaPharm, Inc. lactulose package information,3 “since lactulose solution contains galactose and lactose it should be used with caution in diabetics.”


Transit Time

The normal transit time of lactulose (10 g) in healthy fasting patients, from the mouth to the junction between the small and large intestine (oro-cecal transit time, or OCTT), is approximately 90 minutes. In general, transit times have been found to vary in humans. Given such findings, transit time should be taken into consideration when interpreting breath testing. Substances meant to alter transit time, such as laxatives or prokinetics, should be discontinued 7 days prior to testing. If the patient is constipated, the clinician may extend the length of the limited diet prior to testing, from 24 hours to 48 hours.


Special Instructions for Patients Weighing 100 Pounds or Less/ Paediatric Patients

Follow the instructions on the blue bag for rolling and stapling the bag in accordance with weight. (Note: stapling will not damage the bag or affect the results.) This ensures that air is being collected from the appropriate part of the lungs.

According to Quintron, the manufacturer of the SIBO collection kit, the test is not appropriate for children under 25 pounds. Much of the testing requires strict adherence to collection instructions, which can be a challenge in pediatrics. There is also a strict dietary restriction in the 24 hours prior to testing regarding avoidance of certain foods that may alter the results of the test. It is required that a patient completely fast, with the exception of drinking water, in the 12 hours prior to testing. This may not be amenable in very small children. The package instructions direct the patient to stir the 10 grams (15ml or 3.3g/5ML) of lactulose solution in 8 ounces/240ml of water and drink that solution within 5 minutes after the baseline breath collection. There is not an adjusted dosage for children.

Additionally, bowel frequency and the pediatric microbiome change drastically in the first few years of life. Because of this, research is still developing on how this drastic change may influence the potential development of SIBO, as well as the most effective means to evaluate and diagnose this population. A gold standard testing option for the evaluation of bacterial overgrowth in pediatric populations has yet to be established. However, there is some literature to suggest using breath test measurement to evaluate SIBO in pediatrics.4

If a patient is not a good candidate for taking the SIBO breath test, you may consider utilising the GI Effects Comprehensive stool profile or the Comprehensive Digestive Stool Analysis 2.0 stool profile to glean information about the GI tract. Although these tests are not diagnostic for SIBO, certain biomarkers may suggest SIBO.

  1. Rezaie A, Buresi M, Lembo A, et al. Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus. Am J Gastroenterol. May 2017;112(5):775-784.
  2. Pitz AM, Park GW, Lee D, et. al. Antimicrobial Activity of Bismuth Subsalicylate on Clostridium difficile, Escherichia coli O157:H7, Norovirus, and Other Common Enteric Pathogens. Gut Microbes. 2015;6(2):93-100.
  3. DailyMed Lactulose. National Institutes of Health U.S. National Library of Medicine.
  4. Malik BA, Xie YY, Wine E, Huynh H. Diagnosis and Pharmacological Management of Small Intestinal Bacterial Overgrowth in Children with Intestinal Failure. Can J Gastroenterol. 2011;25(1):41-45.

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