You've got gut symptoms. i-screen has five gut tests. Which one is actually yours?
Bloating, irregular bowels, fatigue, skin flare-ups, IBS-type symptoms - the gut is behind a huge range of complaints, and there isn't one test that covers all of it. i-screen sells several different gut tests because they measure genuinely different things, using different methods, on different samples. This guide walks through what each one actually looks at, so you can match the test to your symptoms rather than guessing.
This is a comparison of what each test measures, not a ranking of which is "best." The right test depends on your symptoms, your budget, and how deep you want to go. All of them are ordered online with no GP referral needed, and none of them diagnose a condition on their own - a NATA-accredited lab analyses your sample and gives you and your practitioner information to work with, not a diagnosis. For a broader look at gut testing options and general questions, see i-screen's Gut & Microbiome hub.
The short version
| Test | Method | Sample | Best suited to | Price | | --- | --- | --- | --- | --- | | Microbiome Check | Stool culture/PCR panel | Stool | A first look at bacteria, parasites, yeast and digestive markers | $239 | | Complete Microbiome Mapping (GI-Map) | DNA-based PCR | Stool | Deeper pathogen, parasite and inflammation detection | $569 | | Microbiomics Advanced Gut Test | Metagenomic shotgun sequencing | Stool | Species-level bacterial mapping, function and diversity | $599 | | SIBO breath tests | Hydrogen/methane breath testing | Breath | Symptoms specifically pointing to small intestinal bacterial overgrowth | $150-$399 |
If you only remember one thing from this table: the stool tests (Microbiome Check, GI-Map, Microbiomics) all look at what's living in your gut. SIBO breath testing looks at something else entirely - bacterial activity in your small intestine. They're not competing options for the same question; they answer different questions.
Microbiome Check - the starting point
Microbiome Check is usually the right place to start if you haven't tested your gut before. It's a stool-based panel screening for beneficial and pathogenic bacteria, parasites, yeast and a set of core digestive markers, giving you a broad first read on what's going on without going as deep (or costing as much) as the two panels below it.
It suits people who want a general check-in on gut balance - bloating, irregularity, or just curiosity about what's living in there - rather than someone already deep into investigating a specific, stubborn issue.
Complete Microbiome Mapping (GI-Map) - built to catch what a general panel might miss
Complete Microbiome Mapping (GI-Map) uses DNA-based PCR technology rather than the older culture-based approach, which means it can detect the genetic fingerprint of a much wider range of specific organisms - including pathogens, parasites and viruses that don't always show up on standard stool culture - alongside gut inflammation and immune markers. It's worth being precise about what PCR-based testing does: it's built for targeted detection of known organisms, not full microbiome community profiling. Under the 2025 international consensus on microbiome testing, only broader sequencing methods, like the metagenomic approach used in Microbiomics below, are considered true microbiome profiling [4].
GI-Map is the right call if you've had ongoing symptoms that haven't resolved, if a previous test came back inconclusive, or if you and your practitioner specifically want pathogen and parasite detection alongside targeted bacterial screening. It's a step up in depth from Microbiome Check, and priced accordingly.
Microbiomics Advanced Gut Test - a broader view of the microbiome itself
Microbiomics Advanced Gut Test uses metagenomic shotgun sequencing. Instead of targeting specific known organisms, it sequences the genetic material in your sample more broadly, giving a detailed picture of bacterial species diversity, digestive function, immune activity and inflammation markers. Shotgun metagenomic sequencing is the method current international consensus guidance recognises as capable of true microbiome community profiling, as distinct from the targeted PCR panels used in GI-Map [4,6].
This is the test for people who want a highly granular view of their microbiome's composition and function - often people already working with a naturopath, nutritionist or integrative GP on a longer-term gut investigation, comparing results over time, or wanting a fuller dataset to work from. It's i-screen's fastest-growing gut product for exactly this reason: as more people become familiar with what PCR and sequencing actually detect, more of them are choosing the deeper option from the outset.
SIBO breath testing - a different question altogether
None of the three stool tests above will tell you about Small Intestinal Bacterial Overgrowth (SIBO), because SIBO isn't about what's in your stool - it's about bacterial activity higher up, in the small intestine, which a stool sample can't capture [1-3]. If bloating, gas or fatigue turn up shortly after eating, or symptoms are worse with certain carbohydrates, SIBO breath testing is the more relevant test, not a stool panel. That said, testing for bloating alone, without other symptoms or risk factors, isn't something every clinical guideline recommends as routine - it's worth talking to your practitioner about whether SIBO testing specifically fits your symptom picture [5].
i-screen offers three tiers, each testing a different combination of sugar substrates:
- SIBO Breath Test - Glucose + Lactulose - the standard option, testing across both the upper and lower small intestine.
- SIBO Breath Test - Lactulose - a simpler single-substrate version.
- SIBO Breath Test - Lactulose + Glucose + Fructose - the fullest breath assessment, adding a fructose substrate that's been studied as a comparable alternative to glucose in some populations [1], for a more complete picture.
All three measure hydrogen and methane gas after drinking a sugar solution, with breath samples collected over a few hours at home using the kit provided, then sent back for lab analysis.
Breath testing accuracy is moderate rather than exact. Measured against the more invasive reference standard of small-bowel fluid culture, published sensitivity and specificity for glucose breath testing run to around 54% and 83%, and for lactulose to around 42% and 71%, with wider ranges reported across older studies [1][3]. That's part of why a breath test result, positive or negative, is best treated as one piece of information to discuss with your practitioner rather than a stand-alone diagnosis.
Can gut symptoms be more than one thing at once?
Often, yes - which is why i-screen also has a Platinum Gut Health Test that bundles the Microbiomics Advanced Gut Test with a food intolerance test, an intestinal permeability (leaky gut) test and a SIBO breath test in one order, for anyone wanting the full picture rather than testing one system at a time. If food reactions look like a bigger piece of your puzzle than the microbiome itself, it's worth reading i-screen's food intolerance testing page before ordering, since IgG food intolerance and gut microbiome imbalance are related but distinct.
It's also common for a gut investigation to surface questions that sit outside the gut itself - inherited patterns in digestion, detoxification or inflammation that a stool or breath test can't see. If that's where your results point, genetic health and DNA testing is often the next step people take, since roughly half of i-screen's gut customers go on to order a DNA test as part of the same investigation.
A quick decision guide by symptom
- General bloating, irregularity, or a first-time check-in - Microbiome Check
- Ongoing symptoms, previous inconclusive results, or suspected parasites/pathogens - Complete Microbiome Mapping (GI-Map)
- Deep, ongoing investigation, working with a practitioner, want maximum detail - Microbiomics Advanced Gut Test
- Symptoms tied to eating: bloating shortly after meals, excess gas, symptoms worse with certain carbs - a SIBO breath test
- Multiple gut-related issues at once (microbiome, food reactions, gut lining, SIBO) - Platinum Gut Health Test
None of these tests diagnose IBS, SIBO or any other condition on their own [4]. They give you markers and patterns relevant to what might be going on, best interpreted alongside your symptoms and with your GP, naturopath or nutritionist.
FAQs
Can I do a stool test and a SIBO breath test at the same time? Yes. Because they test different things (gut microbiome composition versus small intestinal bacterial activity), many people order a stool-based test and a SIBO breath test together, or as the Platinum Gut Health Test bundle, rather than choosing one over the other.
How long do gut test results take? Turnaround varies by test - stool-based panels are typically processed within around two weeks of your sample reaching the lab, while SIBO breath tests are generally quicker to report. Exact timeframes are shown on each test's product page before you order.
What if I've already had a GI-Map or similar test with another provider? You can still order through i-screen - just keep your previous report handy for comparison. If you're mainly looking to track changes over time, ordering the same test again (rather than switching type) makes results easier to compare.
This information is not intended to be a substitute for professional medical advice. i-screen provides wellness and educational testing services only and does not diagnose, treat, cure or prevent any disease or medical condition. Always discuss your results with your doctor or another qualified health professional.
