Concierge SIBO testing · London
SIBO breath test - private in London.
A 2 to 3 hour lactulose or glucose breath test measuring hydrogen and methane, with consultant gastroenterology review and a proper treatment plan if positive.
Why patients choose us
- 01
We explain, not just report
A consultant gastroenterologist talks you through the tracing, the cut-offs, and what a positive result actually means for your gut.
- 02
The right substrate for you
Lactulose or glucose, hydrogen alone or hydrogen and methane. We match the substrate to your symptoms, not the clinic diary.
- 03
A real treatment plan
Guideline-based antibiotics, a properly sequenced low-FODMAP or bi-phasic diet, and motility support if you need it - not a shrug.
Indicative pricing
What a private SIBO breath test costs in London.
Indicative ranges across our partner clinics and laboratories. Send the details and we quote firm figures across two or three options.
In short
A SIBO breath test in our network: £180–£350 all-inclusive, with results back in 3 to 5 days.
| Test or bundle | Indicative range | Duration | Results turnaround |
|---|---|---|---|
| Lactulose hydrogen breath test | £180–£280 | 3 hours | 3–5 days |
| Glucose hydrogen breath test | £180–£280 | 2 hours | 3–5 days |
| Hydrogen and methane combined (SIBO/IMO) | £220–£350 | 3 hours | 3–5 days |
| Trio-smart (H2, CH4, H2S) | £280–£420 | 3 hours | 7–10 days |
| SIBO test + gastro review | £380–£650 | 60 min | Same visit |
| Full IBS work-up bundle | £550–£950 | 90 min | 1–2 weeks |
Prices vary by substrate, whether methane is measured alongside hydrogen, whether a consultant review is bundled in, and how quickly you need the report. We come back with a firm quote within one working day.
What SIBO is
Too many bacteria, in the wrong part of the gut.
Small intestinal bacterial overgrowth (SIBO) is exactly what it sounds like - excess bacteria colonising the small bowel, where the numbers are meant to be low. The result is fermentation where it does not belong: bloating within an hour of eating, gas, altered bowel habit and, over time, malabsorption of iron, B12 and fat-soluble vitamins. When the overgrowth is dominated by methane-producing archaea, the pattern shifts to intestinal methanogen overgrowth (IMO) and constipation. A breath test is how we tell them apart.
The journey
From enquiry to results - what happens, in order.
One consultant gastroenterologist from first message to explained results - usually within a week of preparation.
Phase 1 · Before your test
Concierge, off-stage for you
Phase 2 · The 2 to 3 hour test
In clinic, on the day
Phase 3 · After
Concierge, back on
- 01
Before
You tell us what is going on
A short, confidential form. Symptoms, prior IBS treatments, surgery, and what you want to understand.
- 02
Before
We recommend the right substrate
Within one working day: lactulose, glucose, or a hydrogen and methane combined test - and what each will cost.
- 03
Before
Preparation instructions sent
Antibiotics stopped 4 weeks before, probiotics 2 weeks before, prokinetics 1 week before, low-fermentable diet 24 to 48 hours, then a 12-hour fast.
- 04
On the day
Baseline breath and substrate
A baseline breath sample, then the lactulose or glucose drink, at the clinic or in a supervised home kit.
- 05
On the day
Breath samples every 15 to 20 min
Samples collected for 2 to 3 hours - hydrogen and methane measured across the tracing, not just the peak.
- 06
After
Results reviewed
The tracing is reviewed by a consultant gastroenterologist against North American Consensus cut-offs, usually within one working day.
- 07
After
We explain them
If positive, we arrange targeted rifaximin (add neomycin if methane is high), the right diet phase, and a plan to address the underlying cause.
Typical end-to-end: 5 to 7 days after preparation. Urgent cases: 3 days.
Who benefits from testing
When a SIBO breath test is the right call.
SIBO hides behind a lot of “IBS that will not shift”. These are the clinical patterns that most often turn out to be overgrowth in disguise.
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Bloating unresponsive to IBS treatment
Chronic bloating that has not settled on antispasmodics, low-FODMAP or a peppermint trial deserves a proper look for SIBO.
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Post-cholecystectomy diarrhoea
Loose, urgent stools after gallbladder surgery can reflect bile-salt malabsorption - or bacterial overgrowth downstream.
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Abdominal surgery or adhesions
Blind loops, resections and adhesive obstruction disrupt small-bowel motility and set the stage for overgrowth.
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Motility disorders
Gastroparesis, chronic intestinal pseudo-obstruction and diabetic autonomic neuropathy are classic SIBO backdrops.
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Scleroderma and connective tissue disease
Systemic sclerosis and related conditions slow small-bowel transit - overgrowth is common and treatable.
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Long-term PPI use
Sustained acid suppression removes the stomach’s antibacterial barrier and is a recognised SIBO risk factor.
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Unexplained iron or B12 deficiency
Overgrowth can cause fat, iron and B12 malabsorption - worth testing when the usual work-up is blank.
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Red flag symptoms
Weight loss, blood in the stool, nocturnal diarrhoea or a family history of bowel cancer need endoscopy or colonoscopy - not a breath test.
Available tests
Substrates and gases - what each option measures.
Lactulose is more sensitive, glucose is more specific for proximal SIBO, and adding methane (and, on newer panels, hydrogen sulphide) changes what you can actually treat.
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Lactulose hydrogen breath test
More sensitive but less specific. Lactulose is not absorbed, so it travels the length of the small bowel - useful for distal overgrowth.
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Glucose hydrogen breath test
More specific but only samples the proximal small bowel, because glucose is absorbed within 60 to 90 cm. The right choice for proximal SIBO.
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Hydrogen and methane combined
Adds methane to catch intestinal methanogen overgrowth (IMO) - the archaea-driven pattern behind constipation-predominant symptoms.
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Trio-smart (H2, CH4, H2S)
Newer three-gas test that also measures hydrogen sulphide - the pattern linked to diarrhoea-predominant symptoms and sulphurous wind.
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+ Gastro review
Breath test bundled with a consultant gastroenterologist review, same visit, so a positive tracing becomes a treatment plan on the day.
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Faecal calprotectin
A stool marker to rule inflammatory bowel disease in or out before or alongside the breath test.
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Endoscopy with duodenal aspirate
The reference standard for proximal SIBO - reserved for diagnostic uncertainty or treatment failure.
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Anorectal manometry
Where constipation dominates and biofeedback may be needed alongside methane-targeted treatment.
Our vetted London network
A small panel of clinics, we picked them.
Roseneath Medical, the London Gastroenterology Centre, the London Digestive Centre, HCA Wellington and One Welbeck - the clinics we send SIBO patients to most often, chosen for consultant expertise and laboratory quality.
Selection criteria
How we choose every clinic in our network.
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Consultant gastroenterologists with a specialist interest in functional bowel disease and small-bowel overgrowth
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UKAS-accredited breath-test laboratories reporting both hydrogen and methane against North American Consensus cut-offs
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Consultant prescribing of guideline-based rifaximin, with neomycin or metronidazole where methane is high
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A fast-track colonoscopy or small-bowel imaging pathway when red flags or treatment failure need direct visualisation
Preparation and practicalities
Simple to do - if you follow a few rules.
The breath test is non-invasive and safe, but preparation is everything - antibiotics, probiotics, diet and even a morning run can all change the tracing. We tell you exactly what to do.
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Stop antibiotics four weeks before
Any antibiotic course in the previous four weeks can suppress the overgrowth and cause a false negative. Allow four full weeks after the last dose.
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Stop probiotics two weeks before
Probiotic supplements and live-culture yoghurts alter the fermentation pattern - stop for at least two weeks before the test.
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Hold prokinetics one week before
Erythromycin, prucalopride and similar motility agents change small-bowel transit time and can distort the tracing.
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Low-fermentable diet 24 to 48 hours before
Plain chicken, fish, eggs, white rice, potato and clear broth. No fibre, legumes, dairy, onions, garlic or sweeteners the day before.
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Fast twelve hours before
No food or drink other than plain water for twelve hours before the appointment. No smoking or vaping either - both change breath gases.
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No exercise on the morning
Vigorous exercise on the day of the test can hyperventilate off hydrogen. Take it easy and travel gently.
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PPIs are usually fine
Unlike the H. pylori breath test, PPIs do not need to be stopped for a SIBO breath test. Chronic PPI use is often the reason we are testing.
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Retest timing after treatment
Repeat testing to confirm response is done four to six weeks after antibiotics - sooner is unreliable, later loses the treatment signal.
Reading your report
The breath-test tracing looks intimidating. It isn't.
Whichever laboratory runs the samples, the report follows the same four parts. And a positive SIBO breath test needs a real treatment plan, not just a label - targeted rifaximin (plus neomycin or metronidazole where methane is high), a sequenced low-FODMAP or bi-phasic diet, a prokinetic where motility is the driver, and honest work on the underlying cause.
A quiet reminder
Read the impression first - the tracing is the working.
If you would like us to talk you through the report before any follow-up, just ask.
- 01 Header
Your details, indication and medications
Your details, the clinical question, and every medication that could influence the result - antibiotics, probiotics, prokinetics.
- 02 Technique
Substrate, timing and gases measured
Which substrate was used (lactulose or glucose), the sampling schedule, and whether hydrogen alone or hydrogen and methane were measured.
- 03 Findings
The breath tracing and cut-offs
A rise in hydrogen greater than 20 ppm above baseline within 90 minutes, or methane at or above 10 ppm at any point, meets the North American Consensus criteria for a positive test.
- 04 Impression
The conclusion: read this first
Positive or negative - hydrogen-predominant SIBO, methane-predominant IMO, mixed, or normal - and the treatment implications. Read this first.
Recognised by major UK insurers
Cover varies by policy. Where testing is medically indicated we confirm cover with your insurer before booking.
Frequently asked
Everything we get asked about SIBO breath testing.
Quick answers on fasting, antibiotics, probiotics, diet, insurance and how often to repeat the test.
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Do I need to fast before a SIBO breath test?
Yes. You need to fast for twelve hours before the appointment - plain water only. On top of that, we ask you to eat a low-fermentable diet for the 24 to 48 hours before: plain chicken, fish, eggs, white rice, potato and clear broth. No fibre, legumes, dairy, onions, garlic or artificial sweeteners the day before. We send the full instructions once you book.
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How long do I have to stop antibiotics before the test?
Four full weeks after your last antibiotic dose. Anything sooner and the tracing is likely to give a false negative because the overgrowth is still suppressed. If you have had a recent course, tell us and we will schedule the test accordingly.
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Do I need to hold my probiotics or supplements?
Yes. Stop probiotic capsules and live-culture yoghurts for at least two weeks before the test - they change the fermentation pattern in ways that muddy the tracing. Motility agents such as erythromycin or prucalopride should be paused for one week. Most other medicines are fine, but check with us first.
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Lactulose or glucose - which one should I have?
Lactulose is more sensitive because it travels the whole length of the small bowel, so it picks up distal overgrowth. Glucose is more specific but only samples the proximal 60 to 90 cm. In practice, we lean on lactulose for bloating and diarrhoea-predominant symptoms and glucose when the picture points at proximal SIBO. Some laboratories run both.
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Will my private medical insurance cover a SIBO breath test?
Sometimes. Bupa, AXA Health and Vitality will often authorise the test when it is requested by a consultant gastroenterologist as part of a workup for bloating, malabsorption or persistent IBS symptoms. Cover for self-referred testing is patchy. We confirm authorisation in writing before booking so there are no surprises.
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How often should the test be repeated?
A repeat test to confirm response is done four to six weeks after finishing antibiotics. Beyond that, testing is symptom-led rather than routine - if symptoms recur or a new trigger appears (surgery, a course of antibiotics for something else, a slow-transit flare) it is reasonable to retest, but we would not repeat it every few months in a stable patient.
Related tests
Looking for something else?
-
H. pylori breath test
The 30-minute urea breath test for reflux, gastritis and ulcer work-up.
Learn more -
Colonoscopy
The definitive investigation for red-flag lower-GI symptoms.
Learn more -
IBS
Related condition guide - overlap, differences and when to test.
Learn more -
Anorectal manometry
The right next step when constipation dominates and biofeedback may help.
Learn more
Book a private SIBO breath test
Bloating that will not shift deserves a proper answer.
Tell us what is going on. Within one working day we come back with the right substrate, the right laboratory, a firm quote across two or three options and a consultant to talk you through the tracing.