Gut Testing

Gut Testing Australia

Gut testing divides into two main approaches: stool-based analysis, which examines the microbiome, digestive function, and inflammatory markers from a collected sample, and breath testing, which measures gas produced by bacteria in the small intestine. These are distinct investigations that answer different questions – stool tests map the broader gut environment, while breath tests are specific to bacterial activity in the small intestine.

These tests are most commonly used by people working with a practitioner to investigate persistent digestive symptoms – bloating, altered bowel habits, or symptoms that have not resolved with straightforward dietary changes. In most cases, the appropriate test is guided by clinical context rather than personal preference.

Key principle: The choice between a stool test and a breath test follows from the clinical question – stool analysis maps overall gut ecology and microbiome composition, while breath testing is specific to bacterial overgrowth in the small intestine, so the right test is determined by symptom pattern and practitioner assessment, not by personal preference.

Gut testing products at Fairfield Nutrition

Product Brand Best For Key Details
Doctor’s Data GI 360 Test Doctor’s Data Comprehensive gut investigation Stool-based; broad panel covering microbiome balance, digestion markers, inflammation indicators, and pathogens
Complete Microbiome GI-Map Test Nutripath At-home microbiome assessment Stool-based; at-home collection; analyses bacteria, fungi, parasites, and immune markers across the full gut
Lactulose SIBO Breath Test Small intestinal bacterial overgrowth assessment Breath-based; lactulose substrate; measures hydrogen and methane gas production over a timed collection period

How to choose between gut testing products

The primary decision is whether the clinical question points to the broader gut environment or specifically to bacterial activity in the small intestine.

  • Comprehensive stool analysis: The GI 360 (Doctor’s Data) and GI-Map (Nutripath) both investigate the full gut microbiome, digestion function, and inflammatory markers via stool sample. The GI-Map uses at-home collection, which suits people who prefer convenience or cannot attend a clinic; the GI 360 covers a similarly broad panel and is often chosen based on practitioner preference or the specific markers their protocol requires.
  • SIBO breath testing: The Lactulose SIBO Breath Test is a targeted investigation for bacterial overgrowth in the small intestine, using a breath-based method that is distinct from stool analysis. It is appropriate when symptoms and clinical assessment point specifically toward small intestinal involvement rather than a broader gut ecology question. SIBO symptoms can include bloating (particularly soon after eating), digestive discomfort, food reactivity (particularly to FODMAPs), and changes in bowel movements

If you are uncertain which test is appropriate for your situation, your practitioner is the most reliable guide – the right choice follows from your symptom history and clinical context, not from the tests themselves.


All gut testing products stocked at Fairfield Nutrition are shown below.