A clinician-reviewed breath test that detects Small Intestinal Bacterial Overgrowth (SIBO) and Intestinal Methanogen Overgrowth (IMO) from the comfort of your home — with a diagnostic report prepared by an OMED doctor.
If you’ve been experiencing persistent digestive symptoms that haven’t resolved — or that standard tests haven’t explained — SIBO may be worth investigating. It’s far more common than most people realise, and is a frequent underlying driver of IBS.
This test may be right for you if you’re experiencing:
The test uses a clinically validated hydrogen and methane breath analyser developed by Owlstone Medical — one of the world’s leading breath analysis companies. By measuring the gases produced by bacteria fermenting in your small intestine, it can detect both of the main subtypes of small intestinal overgrowth.
| Gas / Marker | What it detects | Threshold for positive |
|---|---|---|
| Hydrogen (H2) | Bacterial fermentation in the small intestine — indicates hydrogen-dominant SIBO | Rise of ≥ 20 ppm from baseline by 90 minutes |
| Methane (CH2) | Methanogen overgrowth (IMO) — associated with constipation-predominant symptoms | Peak level of ≥ 10 ppm at any point |
At the time of ordering, I will select the most appropriate substrate for your case:
⚠️ Please note: all substrates must be purchased directly through OMED Health — using substrates from any other source will invalidate your results. Replacement substrates are provided free of charge in the event of a failed test.
The test is completed entirely at home using the OMED Breath Analyser device and app. Once your samples are collected, an OMED doctor reviews your results and prepares a diagnostic report. The full test takes approximately 2.5 hours.
The OMED SIBO / IMO breath test has several practical advantages over a standard postal breath test:
Please familiarise yourself with the breath sampling process before starting a SIBO test by watching the video guides below.
Following the preparation requirements carefully is essential for accurate results. As preparation begins weeks before your test, please read all of the below carefully.
Never stop prescription medications without speaking to your doctor first. If you have any questions about your eligibility for this test, if you use insulin or take medication for diabetes, please get in touch before ordering.
These interventions can significantly alter gut bacteria and affect test accuracy.
Foods & Beverages to Avoid
These foods ferment in the gut and can elevate baseline gas levels.
A low-fermentation diet the day before testing is a critical part of preparation. Stick strictly to the following foods and drinks only. All the necessary instructions will be available via the app.
Allowed foods & drinks:
Your results will be visible in the OMED Health App immediately on completion. An OMED doctor will then review your data and prepare a diagnostic report, which will also be available through the app and shared with me via the practitioner portal.
Interpreting your results is not included in the test price. Once your doctor’s report is ready, you can book an initial consultation (with test results) with me here to go through your findings in detail and discuss personalised next steps.
OMED Health Terms and Conditions apply to every purchase made. You should read these before you place an order (or ask
Anna Pinnock Nutrition to do so): Terms And Conditions Feb 2026 – OMED Health.
What happens if my test fails or I miss a sample?
If you accidentally close the app mid-test, you can reopen it and continue — as long as your next sample is provided within the permitted timeframe. If 2 consecutive samples are missed, the test will be invalidated. If your baseline hydrogen reading is too high (suggesting suboptimal preparation), the app will notify you. In the event of a failed test where no diagnosis can be obtained, replacement substrates will be provided free of charge so you can repeat it.
How is glucose different from lactulose, and which should I use?
Glucose is absorbed quickly in the upper small intestine and is better for detecting SIBO in the proximal gut, with fewer false positives. Lactulose travels the full length of the small intestine and is better suited for detecting overgrowth further along the gut. I will review your symptoms and case history and select the most appropriate substrate for you when placing your order.
What is SIBO?
SIBO (Small Intestinal Bacterial Overgrowth) occurs when bacteria that should be in the large intestine migrate and proliferate in the small intestine, where they ferment food and produce excess hydrogen and/or methane gas. It’s estimated to underlie a significant proportion of IBS diagnoses, and is often missed by standard GP investigations. IMO (Intestinal Methanogen Overgrowth) is a closely related condition, typically associated with constipation-predominant symptoms, detected via elevated methane readings.
How long does the test take?
The test itself takes approximately 2.5 hours to complete at home. You’ll provide a baseline breath sample, drink the substrate solution, then provide 9 further samples every 15 minutes. The OMED app guides you through every step automatically.
Can children and babies use the OMED Breath Analyser device?
No – this test is available to individuals aged 18 or over.
Do I need a doctor’s referral?
No referral is needed. I will order the test on your behalf through the OMED practitioner portal after reviewing your case. You can get in touch via the contact page or book a free enquiry call to discuss whether this test is right for you.
Is results interpretation included in the price?
The test price includes the Breath Analyser device, the substrate, and the diagnostic report from an OMED doctor. It does not include a consultation with me to interpret your results in the context of your symptoms, diet, and health history. Once your report is ready, you’ll have the option to book a results consultation (£195) where we’ll go through your findings together and I’ll create personalised recommendations for next steps.
What happens to my device after testing?
The OMED Breath Analyser is on loan for the duration of your test (up to 12 weeks). Once your testing is complete, return it using the prepaid envelope included with your kit. If you need a retest within the 12-week window, the device can be used again — each retest uses a new substrate and is priced at £80.
Can I do this test if I’m on antibiotics?
No — you need to have been off all systemic (oral or intravenous) antibiotics for at least 4 weeks before testing. You also need to have stopped any probiotics (including Actimel or similar) at least 1 week before. Testing too soon after antibiotics will produce unreliable results and is likely to lead to false negatives.
Is the test available outside England?
The test is available to individuals aged 18 and over living in Great Britain — that’s England, Scotland, and Wales. It is not currently available in Northern Ireland. The service is not available to individuals outside the UK.
