Selph Gut health

SIBO Test

A breath test measuring hydrogen and methane after drinking a lactulose solution, used to help assess small intestinal bacterial overgrowth (SIBO). Suited to people with ongoing unexplained bloating, diarrhoea or constipation.

  • At-home test
  • Doctor reviewed
Sample
Breath
Collection
At-home breath test by post
Results in
7–8 days
Biomarkers
2
Doctor reviewed
Yes
Tests for
  • Hydrogen level
  • Methane level

Test specifications

Provider
Selph
Sample type
breath
Collection method
at-home breath test by post
Turnaround time
7–8 days
Biomarkers tested
2
At-home test
Yes
Doctor reviewed
Yes
Gender focus
Both

What's tested

2 biomarkers as listed by Selph.

Hydrogen Methane Breath Test

  • Hydrogen level
  • Methane level

About this test

The SIBO Test measures hydrogen and methane in your breath after drinking a lactulose solution, a method commonly used to help assess whether small intestinal bacterial overgrowth could be contributing to symptoms such as bloating, diarrhoea or constipation. A raised level of either gas can point towards bacterial overgrowth in the small intestine, though the test does not diagnose the condition on its own.

There's no other test in Selph's own range for direct comparison, so this sits outside a named comparison group on this site. Against the wider set of 35 similarly sized gut health tests we track, its £175 price is about 62% above the £108 median, and its turnaround of around 7 to 8 days is longer than the one-to-two day turnaround typical of Selph's blood tests.

The value for money score is low as a result of that higher cost, and collection convenience scores below Selph's blood tests because of the longer wait for results, even though the breath sample itself is collected entirely at home. Clinical depth actually scores well, placing this two-marker test in the 68th percentile among the gut health tests we track, and trust signals and results and follow-up both score highly thanks to the doctor-reviewed report; Selph also offers a paid follow-up consultation to discuss results and possible next steps.

Who is it for?

This suits people with ongoing, unexplained bowel symptoms who want to investigate whether bacterial overgrowth could be a factor, ideally alongside advice from a GP. Because of its higher price and longer turnaround compared with similarly sized gut health tests, it's better suited to those who specifically want a SIBO breath test rather than a general first check on gut health.

How it works

You follow a low-fermenting diet for 24 hours, then take a baseline breath sample before drinking a lactulose solution and collecting six further breath samples over 150 minutes at home. You post the samples to Selph's lab, where hydrogen and methane levels are measured; results take around 7 to 8 days and are reviewed by a Selph doctor, with a paid follow-up consultation available if you want to discuss treatment options.

Pros & cons

Pros

  • Measures both hydrogen and methane, covering two SIBO-related gas patterns
  • Entire multi-step breath protocol is done at home
  • Doctor-reviewed report, with a paid follow-up consultation available
  • Clinical depth scores well for a 2-marker test, in the 68th percentile of gut tests tracked

Cons

  • Costs about 62% more than the £108 median for similarly sized gut tests
  • Results take around 7 to 8 days, longer than Selph's blood tests
  • Sits outside a named comparison group, making it harder to weigh against direct rivals

Our editorial score

Compare Health Test Score Costs 62% more than the typical gut-health test
Editorial confidence: 10.0/10

Score breakdown

  • Clarity and documentation 9.0/10

    The listing publishes a detailed description, the full biomarker list, a stated turnaround, clear collection options, the sample type; it does not state what the report looks like.

  • Clinical depth 8.6/10

    2 biomarkers, placing it in the 68th percentile of gut health tests we track.

  • Collection convenience 6.0/10

    Can be done at home; results in around 8 days.

  • Results and follow-up 7.0/10

    Results are reviewed by a doctor.

  • Trust signals 10.0/10

    Trustpilot 4.9 from 71,592 reviews; accredited lab (UKAS ISO 15189 partner labs (Inuvi, TDL)); CQC registered; doctor review as standard.

  • Value for money 3.4/10

    £175.00 against a median of £108.00 for the 35 similarly sized gut health tests we track (+62%).

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