Stool Tests Explained: What They Can and Can't Tell You

Medically reviewed and written by Dr Zeeshan Afzal, MBBS — Medical Content Lead, Welzo. Last updated: August 2026. This article is for general information and does not replace personalised medical advice.

A stool test in the UK can do something no blood test can: it samples the material that has physically travelled the length of your gut. That makes stool testing one of the most useful — and most misunderstood — tools in digestive medicine. Some stool tests are rigorously validated and sit at the centre of NHS cancer and inflammatory bowel disease pathways. Others are sold direct to consumers with confident-sounding reports that current evidence simply does not support. This guide explains every category of stool test available in the UK, what each one genuinely measures, where the evidence is strong, and — just as importantly — the questions a stool sample cannot answer. If you are starting from the beginning, our complete guide to gut health in the UK sets the wider context, and our gut health range and probiotics collection cover the supplement side once you have a diagnosis. For readers already researching specific options, we have detailed guides on Akkermansia muciniphila, modified citrus pectin powder, ultra-purity berberine and ultra-purity TUDCA. You may also want to read our companion pieces on gut microbiome testing in the UK, the faecal calprotectin test, the Bristol Stool Chart and when to see a GP about stomach symptoms.

Table of contents

• What is a stool test, and why is stool so informative?
• The three categories of stool test available in the UK
• Stool test comparison table: what each one measures
• FIT: the faecal immunochemical test
• Faecal calprotectin: measuring gut inflammation
• Stool culture, PCR panels and parasite testing
• H. pylori stool antigen testing
• Faecal elastase and digestive enzyme output
• Other stool markers: fat, bile acids, secretory IgA, zonulin
• Microbiome and "gut health" stool tests: the evidence
• What a stool test cannot tell you
• How to prepare for and collect a stool sample properly
• Understanding your results — including normal results with ongoing symptoms
• NHS versus private stool testing in the UK
• What to do after your results
• Red flags: when to seek urgent medical advice
• Frequently asked questions
• References

What is a stool test, and why is stool so informative?

A stool test is any laboratory analysis performed on a sample of faeces. Depending on which test is ordered, the laboratory may look for human proteins that have leaked from the gut wall, human haemoglobin from bleeding, enzymes from the pancreas, the genetic signatures of bacteria and parasites, or the composition of the microbial community itself.

Stool is uniquely informative because it is a composite of everything that happened along roughly eight metres of small intestine and 1.5 metres of colon: undigested food residue, sloughed intestinal cells, digestive secretions, immune proteins, and an enormous microbial population. Roughly a quarter to a third of the dry weight of stool is bacterial mass. When something goes wrong upstream — bleeding, inflammation, poor enzyme output, infection — the evidence frequently ends up in the sample.

What stool testing replaced

Historically, investigating lower gastrointestinal symptoms meant going straight to colonoscopy. Stool biomarkers changed that. A validated stool test allows clinicians to triage: identify who genuinely needs an invasive camera test, and reassure who does not. This is why the NHS now posts millions of home test kits every year rather than scoping everyone with a change in bowel habit.

Where stool testing sits in the diagnostic hierarchy

It helps to think of stool tests as triage and monitoring tools rather than diagnostic endpoints. Almost no stool result is a diagnosis in itself. A positive FIT does not diagnose bowel cancer; it earns you a colonoscopy. A raised calprotectin does not diagnose Crohn's disease; it earns you a specialist referral. Understanding this distinction prevents both false reassurance and unnecessary alarm.

Figure 1: A stool sample carries four distinct layers of information. Alt text for CMS: "Diagram showing the four categories of information found in a stool sample — human proteins, blood, digestive enzymes and microbes."

The three categories of stool test available in the UK

Almost every stool test marketed in Britain falls into one of three groups, and confusing them is the single most common source of misunderstanding.

1. NHS diagnostic stool tests

These are validated, externally quality-assured tests used within national clinical pathways: FIT, faecal calprotectin, stool culture and PCR, H. pylori stool antigen, faecal elastase, and Clostridioides difficile toxin testing. They are ordered because a clinician has a specific question, and the result changes what happens next.

2. Private clinical stool tests

The same validated assays, ordered privately for convenience or speed, usually through a UKAS-accredited laboratory. The science is identical; you are paying for access, not a different test. Costs typically range from roughly £40–£90 for a single marker to £150–£300 for a multi-marker panel.

3. Direct-to-consumer wellness and microbiome tests

These sequence bacterial DNA or measure non-standardised "functional" markers, then generate a personalised report — often with product recommendations attached. This category is not regulated as a medical diagnostic in the UK, and the evidence base is considerably weaker. We cover it in detail in the microbiome section below and in our dedicated UK microbiome test comparison.

Stool test comparison table: what each one measures

FIT: the faecal immunochemical test

FIT is the most consequential stool test in Britain. It uses antibodies specific to human haemoglobin to detect blood in faeces at concentrations far below what the eye can see.

How FIT is used in NHS bowel cancer screening

NHS bowel cancer screening now offers a free home FIT kit to everyone aged 50 to 74 in England every two years, with people aged 75 and over able to request a kit by calling the screening helpline on 0800 707 60 60. Scotland and Wales also screen from age 50.

In January 2026, NHS England announced a significant change: the haemoglobin level that triggers further investigation in the screening programme was lowered from 120 micrograms per gram of faeces to 80, a change expected to generate around 35% more screening colonoscopies each year and detect thousands more cancers and pre-cancerous polyps. Uptake, however, remains the weak link. NHS England reported in July 2026 that just over half of 54-year-olds completed screening in 2024–25, compared with more than seven in ten of those aged 70 to 74, while around 100 cancers a week were being diagnosed through the programme.

How FIT is used for people with symptoms

Symptomatic testing is different. NICE recommends quantitative FIT to guide referral for adults with signs or symptoms suggestive of colorectal cancer, with referral on the suspected cancer pathway when the result is at least 10 micrograms of haemoglobin per gram of faeces — a much lower and more sensitive threshold than screening. Crucially, NICE also states that referral should not be delayed in the absence of a FIT result if there is clinical concern, and that safety-netting must be in place for people who do not return a sample.

How accurate is FIT?

The systematic review that informed NICE guidance found that at a 10 µg Hb/g cut-off, a single-sample FIT using the OC-Sensor analyser had a sensitivity of 92.1% (95% CI 86.9–95.3%) for colorectal cancer, with specificity around 85.8%. Performance drops when the target condition is widened to include higher-risk adenomas.

What FIT cannot tell you

• It cannot diagnose cancer. A positive FIT means blood is present. Haemorrhoids, anal fissures, IBD, polyps and diverticular disease all cause bleeding. Confirmation requires colonoscopy or CT colonography.
• It cannot fully exclude cancer. Roughly 8% of cancers are missed at a 10 µg/g threshold. Persistent symptoms after a negative FIT still warrant review — this is exactly what safety-netting is for.
• It cannot locate the bleeding. FIT gives no information about where in the bowel blood originated.
• It cannot assess your microbiome, inflammation, or digestion. It measures one molecule.

Figure 2: UK FIT thresholds compared. Alt text for CMS: "Bar chart comparing FIT haemoglobin thresholds: 10 micrograms per gram for symptomatic referral, 80 for NHS screening from January 2026, down from 120 previously."

Faecal calprotectin: measuring gut inflammation

Calprotectin is a calcium-binding protein that makes up a large proportion of the cytosolic protein in neutrophils — the white blood cells that flood into the bowel wall during inflammation. When neutrophils migrate into the intestinal lumen, calprotectin ends up in stool, where it is remarkably stable at room temperature for several days.

Why the test matters

Its central job is separating inflammatory bowel disease from irritable bowel syndrome. NHS laboratories describe the test as having sensitivity and specificity of approximately 90% for distinguishing inflammatory from non-inflammatory bowel disorders. That distinction is enormously valuable: IBS does not raise calprotectin, so a genuinely low result in a young patient with chronic symptoms makes IBD very unlikely and can spare an unnecessary colonoscopy. If your result points towards IBS, our guides to IBS subtypes, the low FODMAP diet and supplements for IBS are the natural next reads.

How results are usually interpreted

Thresholds vary between laboratories and local care pathways, so always interpret your number against the range printed on your own report. A widely used NHS primary care structure looks broadly like this:

NICE first supported calprotectin testing in primary care in 2013 for adults under 45 with ongoing lower gastrointestinal symptoms where referral was being considered and cancer was not suspected. Real-world uptake has been patchy: a large study using UK primary care records found that only 3.1% of patients with eligible symptoms had received a calprotectin test after national recommendations were published.

What raises calprotectin other than IBD

• NSAIDs such as ibuprofen, naproxen and diclofenac — NHS guidance commonly advises stopping these for four weeks before testing if your doctor agrees it is safe. See our guide to ibuprofen and stomach damage.
• Proton pump inhibitors — relevant if you take omeprazole long term.
• Recent gastrointestinal infection, including after a stomach bug.
• Colorectal polyps and some malignancies.
• Coeliac disease and diverticular disease.
• Increasing age, and infancy.

What calprotectin cannot tell you

It cannot distinguish Crohn's disease from ulcerative colitis, cannot tell you where in the bowel the inflammation is, and cannot rule out microscopic colitis reliably. A raised result always requires a specialist to look. If you are already diagnosed, our Crohn's diet and ulcerative colitis diet guides go further.

Stool culture, PCR panels and parasite testing

If diarrhoea is severe, bloody, persistent beyond seven days, follows foreign travel, or occurs after antibiotics, your GP will usually request microbiological testing.

Traditional culture and microscopy

Stool culture grows bacteria such as Salmonella, Campylobacter, Shigella and E. coli O157. Microscopy for ova, cysts and parasites looks for Giardia, Cryptosporidium and helminths. Because parasites are shed intermittently, three samples on separate days are often requested — a single negative does not exclude infection.

Multiplex PCR panels

Most UK laboratories now use molecular panels that detect the DNA or RNA of a dozen or more pathogens in one run, with results often available within 24 hours. The trade-off is that PCR detects genetic material from organisms that may be dead or simply passing through, so a positive result must always be interpreted alongside symptoms.

C. difficile testing

Testing for Clostridioides difficile is a two-step process: a screening test for the GDH antigen, then a test for the toxin that actually causes disease. Only patients with unformed stool are tested, because carriage without illness is common. Our guides on probiotics and C. difficile, probiotics after antibiotics and Saccharomyces boulardii cover the aftercare evidence. Travellers should also see our pieces on traveller's diarrhoea and travel probiotics.

H. pylori stool antigen testing

Helicobacter pylori colonises the stomach lining and is a major cause of peptic ulcers and a recognised risk factor for gastric cancer. NICE recommends testing with a carbon-13 urea breath test, a stool antigen test, or locally validated laboratory serology.

The washout rules that make or break the result

This is the single most important practical point about H. pylori stool testing, and it is where most false negatives come from. NICE specifies a two-week washout after proton pump inhibitors and no antibiotics in the four weeks before testing. Acid suppression drives the bacteria into a state where they shed insufficient antigen to be detected — so testing while still taking omeprazole or lansoprazole can produce a negative result in someone who is genuinely infected.

After eradication treatment, retesting to confirm cure is standard practice, and a urea breath test is generally preferred for that purpose. Read more in our guides to H. pylori in the UK, H. pylori testing, gastritis and stomach ulcers.

Faecal elastase and digestive enzyme output

Faecal elastase-1 is a pancreas-specific enzyme that survives transit through the gut largely intact, making its concentration in stool a reasonable proxy for pancreatic exocrine function. UK laboratory reference ranges are consistent: above 200 µg/g indicates normal exocrine function, 100–200 µg/g suggests mild to moderate insufficiency, and below 100 µg/g indicates severe pancreatic exocrine insufficiency. Helpfully, the test is not affected by pancreatic enzyme replacement therapy, so patients can continue their medication.

When it is worth testing

Consider it if you have pale, greasy, floating, foul-smelling stools, unexplained weight loss, fat-soluble vitamin deficiency, chronic pancreatitis, or long-standing diabetes with malabsorptive symptoms. One important caveat: loose or watery samples dilute elastase and can produce falsely low results, so a formed sample matters.

What it cannot tell you

A normal elastase does not exclude mild insufficiency, and the test says nothing about brush-border enzymes such as lactase. If you suspect a disaccharide problem, see our guides to lactose intolerance, how to take digestive enzymes and enzymes versus probiotics.

Other stool markers: fat, bile acids, secretory IgA, zonulin

Faecal fat

The classic 72-hour faecal fat collection quantifies malabsorption but is unpleasant, unpopular and largely replaced by faecal elastase and breath testing.

Bile acid malabsorption

Faecal bile acid measurement and serum 7αC4 are used in some centres, but the established UK diagnostic test is SeHCAT — a nuclear medicine scan, not a stool test. This is a common misconception. See our guide to bile acid malabsorption.

Secretory IgA, zonulin and beta-glucuronidase

These appear on many private "comprehensive digestive" panels. Faecal zonulin in particular is marketed as a leaky gut marker, but the assays have been repeatedly criticised for questionable specificity — some commercial kits appear to detect proteins other than zonulin itself. Intestinal permeability is a real physiological phenomenon, but no stool marker is validated to measure it in an individual patient. We examine this in detail in the zonulin test, is leaky gut real? and gut barrier function.

Short-chain fatty acids

Faecal SCFA levels are genuinely interesting in research, but they are difficult to interpret clinically because faecal concentration reflects the balance between production and absorption — low faecal butyrate could mean poor production or excellent absorption. Our guides to short-chain fatty acids and butyrate supplements explain the biology.

Microbiome and "gut health" stool tests: what the evidence actually shows

This is where expectation and evidence diverge most sharply. Direct-to-consumer microbiome tests sequence bacterial DNA from your sample and return a report describing your "diversity score", the abundance of named species, and frequently a set of dietary and supplement recommendations.

What the research says

An international multidisciplinary expert panel published a consensus statement in The Lancet Gastroenterology & Hepatology in 2024 concluding that evidence supporting the clinical usefulness of microbiome testing is scarce, and warning that commercial direct-to-consumer tests are offered without consensus on regulation or proven clinical value — with the potential for considerable waste of individual and healthcare resources.

The analytical problem is at least as serious as the clinical one. Researchers evaluated seven direct-to-consumer gut microbiome testing services using a standardised reference faecal material developed by the US National Institute of Standards and Technology. They found major discrepancies both within and between providers, with variability between companies on the same scale as the biological variability between different human donors. In plain terms: the difference between two companies analysing the same stool can be as large as the difference between two different people's guts.

A related editorial highlighted that collection, storage, processing and analysis methods are not standardised, replicability between runs can be low, and consumer results are often benchmarked against unrepresentative internal databases built from the company's own previous customers.

What microbiome tests can reasonably tell you

• A broad, non-diagnostic snapshot of bacterial composition on the day you sampled.
• A rough sense of diversity, which correlates at population level with dietary fibre and plant variety.
• A motivational nudge — several products bundle genuinely evidence-based dietary advice around the report.

What they cannot tell you

• Whether you have a disease. There is no validated microbiome signature for diagnosing IBS, IBD, SIBO or candida overgrowth from stool sequencing.
• Which specific probiotic strain you personally need. Strain selection remains evidence-led by condition, not by test result — see how to choose a probiotic.
• Whether a named "bad" bacterium is causing your symptoms. Presence is not causation.
• A stable picture. Composition shifts with diet, sleep, medication, travel and transit time within days.

None of this means the microbiome is unimportant — it is one of the most exciting areas in medicine. It means that the gap between population-level science and individual-level prediction is still wide. Our related reading covers microbiome diversity, gut dysbiosis, how to increase bacterial diversity, the 30 plants a week target and Akkermansia versus conventional probiotics.

What a stool test cannot tell you

Bringing the limitations together, because this is the question most readers arrive with:

Figure 3: Matching symptoms to the appropriate stool test. Alt text for CMS: "Flow diagram matching common digestive symptoms to the appropriate UK stool test, including FIT, faecal calprotectin, stool culture, H. pylori antigen and faecal elastase."

How to prepare for and collect a stool sample properly

Sample quality determines result quality. A surprising number of tests are rejected or produce misleading results because of collection errors.

Before you collect

• Check whether medication washouts apply — NSAIDs for calprotectin, PPIs and antibiotics for H. pylori. Never stop prescribed medication without speaking to your doctor first.
• Some laboratories advise avoiding alcohol and smoking for 24 hours before collecting a calprotectin sample.
• Use the container supplied. Additives and preservatives differ between assays; the wrong tube can void the test.
• Avoid sampling during heavy menstrual bleeding for FIT, and do not collect if you have visibly bleeding haemorrhoids that day.

Collecting the sample

1. Empty your bladder first — urine contaminates the sample.
2. Catch the stool before it touches the toilet water. Clean paper spread across the bowl, or a paper collection bowl, works well.
3. Fill to the marked line, no more. Overfilled tubes are frequently rejected on safety grounds.
4. For FIT kits, scrape the grooved stick across several different areas of the stool surface.
5. Label with your full name, date of birth and the exact date and time of collection.
6. Return promptly. Most kits should reach the laboratory within 24–72 hours; refrigerate in a sealed bag in the meantime if your instructions say so.

If the sample is very loose or very hard

Extremes of stool form affect several assays — watery samples dilute elastase, and very hard samples can be difficult to process. If your bowel habit is at either end of the Bristol Stool Chart, mention it when you return the kit. Our guides to constipation relief and magnesium for constipation may help in the meantime.

Understanding your results — including normal results with ongoing symptoms

Three principles will serve you well when your report arrives.

1. Read your own laboratory's reference range

Assay platforms differ. A calprotectin of 60 µg/g may be flagged differently by two laboratories. The number on your report only means something against the range printed beside it.

2. A normal result does not mean nothing is wrong

This is the most emotionally difficult outcome and the most common. Normal FIT, normal calprotectin and negative cultures alongside real, disruptive symptoms is a very typical pattern in functional gut disorders — and functional does not mean imaginary. Disorders of gut–brain interaction involve measurable changes in visceral sensitivity, motility and central processing that these tests were never designed to detect. Our guides to the gut–brain connection, the vagus nerve and supplements for bloating explore this further.

3. Trends beat single readings

For anyone with diagnosed IBD, serial calprotectin measurements are far more informative than a single value, because the trajectory reflects response to treatment.

NHS versus private stool testing in the UK

A practical note: if you pay for a private test and the result is abnormal, take the full report to your GP. NHS clinicians may repeat validated tests through their own accredited laboratory before acting, particularly for results that trigger urgent pathways. More detail in our guides to stool testing in the UK, the gut health blood test and bowel cancer screening.

What to do after your results

If a stool test identifies a specific condition, treatment follows that diagnosis — eradication therapy for H. pylori, targeted antibiotics for confirmed pathogens, specialist management for IBD, enzyme replacement for pancreatic insufficiency.

If your results are reassuring but symptoms persist, the highest-value interventions are unglamorous and well-evidenced:

• Increase plant diversity and fibre gradually. See how to increase fibre, high fibre foods and prebiotic foods.
• Include fermented foods regularly. See fermented foods and kefir benefits.
• Consider a targeted probiotic chosen by condition rather than by test result. Browse the Welzo probiotics range, or read best probiotics UK, when to take probiotics and how long probiotics take to work.
• Address sleep, stress and movement — see gut health and sleep.
• Explore targeted options such as Akkermansia, modified citrus pectin, berberine or TUDCA from the wider gut health collection, discussing any supplement with your doctor if you take prescription medication.

Red flags: when to seek urgent medical advice

Do not wait for a stool test result — or order one privately instead of seeing a doctor — if you have:

• Visible blood in your stool, or black tarry stools
• Unexplained weight loss
• A persistent change in bowel habit lasting more than three weeks
• A new abdominal or rectal mass
• Difficulty swallowing, or persistent vomiting
• Iron deficiency anaemia without an obvious cause
• Severe abdominal pain, fever, or signs of dehydration
• A family history of bowel cancer or IBD alongside new symptoms

Contact your GP, or NHS 111 if urgent. Our guide on when to see a GP about stomach symptoms covers this in more depth.

Frequently asked questions

What does a stool test show in the UK?

It depends entirely on which test is ordered. FIT shows hidden blood, calprotectin shows bowel inflammation, culture and PCR show infection, H. pylori antigen shows stomach infection, and elastase shows pancreatic enzyme output. No single stool test screens for everything, which is why your GP selects one based on your specific symptoms.

How much does a private stool test cost in the UK?

Single markers such as calprotectin or FIT typically cost around £40–£90 privately, combined panels £150–£300, and consumer microbiome tests roughly £100–£250. NHS testing is free when clinically indicated, and the FIT screening kit is posted automatically to everyone aged 50 to 74 in England.

Can a stool test detect bowel cancer?

Not directly. FIT detects human haemoglobin in stool, which can be an early sign of bowel cancer, but a positive result requires colonoscopy or CT colonography to confirm a diagnosis. FIT is highly sensitive at the symptomatic threshold but not perfect, so persistent symptoms after a negative result should always be reviewed.

Can a stool test detect IBS?

No. IBS is a clinical diagnosis made on symptom pattern once other conditions have been excluded. Stool tests contribute by ruling things out — a normal calprotectin makes inflammatory bowel disease unlikely, which supports an IBS diagnosis without proving it.

Do I need to stop taking medication before a stool test?

Sometimes. NSAIDs can raise calprotectin and are often stopped for four weeks beforehand if safe to do so. For H. pylori stool antigen testing, NICE specifies a two-week washout after proton pump inhibitors and four weeks after antibiotics. Never stop prescribed medication without medical advice.

Are gut microbiome stool tests worth it?

For diagnosing disease, no. An international expert consensus published in 2024 concluded that evidence for the clinical usefulness of microbiome testing is scarce, and analytical testing of commercial services using standardised reference material found variability between providers comparable to the biological variability between different people. They can still be interesting as a general wellness snapshot, provided you treat the report as exploratory rather than diagnostic.

How long do stool test results take?

NHS bowel screening FIT results usually arrive within two weeks. Calprotectin and elastase typically take one to two weeks, molecular PCR panels are often reported within 24–48 hours, and private laboratories commonly return results in five to seven working days.

Can a stool test detect parasites reliably?

Partially. Parasites are shed intermittently, so microscopy on a single sample can miss infection — which is why three samples on separate days are often requested. PCR panels have improved detection considerably, though a positive PCR indicates genetic material rather than proving active disease.

What if my stool test is normal but I still feel unwell?

This is common and does not mean your symptoms are dismissed. Normal results usefully exclude inflammation, bleeding and infection, which points towards a disorder of gut–brain interaction such as IBS or functional dyspepsia. These are real conditions with real treatments, including dietary approaches, gut-directed psychological therapies and specific medications.

Can I do a stool test at home in the UK?

Yes. The NHS screening FIT kit is designed for home use, GPs routinely issue home collection kits for calprotectin and infection screening, and many private laboratories post kits with prepaid return packaging. The laboratory analysis still happens in an accredited facility — only the collection happens at home.

References

1. NHS. Bowel cancer screening. https://www.nhs.uk/tests-and-treatments/bowel-cancer-screening/
2. NHS England. NHS to detect and prevent thousands more bowel cancers with more sensitive screening, January 2026. https://www.england.nhs.uk/2026/01/nhs-detect-prevent-thousands-more-bowel-cancers-more-sensitive-screening/
3. NHS England. NHS urges people in their 50s to return bowel screening kits, July 2026. https://www.england.nhs.uk/2026/07/nhs-urges-people-50s-return-bowel-screening-kits-100-cancers-found-week/
4. NICE. Quantitative faecal immunochemical testing to guide colorectal cancer pathway referral in primary care (DG56), recommendations. https://www.nice.org.uk/guidance/dg56/chapter/1-Recommendations
5. Westwood M, et al. Faecal immunochemical tests to triage patients with lower abdominal symptoms: systematic review informing NICE DG30. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5654140/
6. South Tees Hospitals NHS Foundation Trust. Faecal calprotectin — clinical use and pathway thresholds. https://www.southtees.nhs.uk/services/pathology/tests/calprotectin/
7. Faecal calprotectin testing in UK general practice: a retrospective cohort study using The Health Improvement Network database. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8510694/
8. Northern Lincolnshire and Goole NHS Foundation Trust. Faecal calprotectin test — patient information and NSAID guidance. https://www.nlg.nhs.uk/resources/faecal-calprotectin-test/
9. NICE. Quality statement 3: testing conditions for Helicobacter pylori (QS96). https://www.nice.org.uk/guidance/qs96/chapter/quality-statement-3-testing-conditions-for-helicobacter-pylori
10. Newcastle Hospitals Laboratories. Faecal elastase reference ranges. https://laboratories.newcastle-hospitals.nhs.uk/test-directory/elastase-faecal/
11. North Bristol NHS Trust. Faecal elastase test information. https://www.nbt.nhs.uk/severn-pathology/requesting/test-information/faecal-elastase
12. Ianiro G, et al. International consensus statement on microbiome testing in clinical practice. The Lancet Gastroenterology & Hepatology, 2024. https://pubmed.ncbi.nlm.nih.gov/39647502/
13. Direct-to-consumer microbiome testing needs regulation. The Lancet Gastroenterology & Hepatology, 2024. https://www.thelancet.com/journals/langas/article/PIIS2468-1253(24)00163-8/fulltext
14. Evaluating the analytical performance of direct-to-consumer gut microbiome testing services. Communications Biology, 2026. https://www.nature.com/articles/s42003-025-09301-3
15. Patient experiences and expectations of faecal immunochemical testing for investigation of colorectal cancer symptoms. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12086939/

About the author

Dr Zeeshan Afzal, MBBS is a practising doctor and Medical Content Lead at Welzo. He writes and reviews Welzo's digestive health content, with a focus on translating NHS and NICE guidance into accurate, accessible information for UK patients. All Welzo health content is reviewed against current national guidance and peer-reviewed literature.

Medical disclaimer

This article is for general information only and is not a substitute for individual medical advice, diagnosis or treatment. Always speak to your GP or a qualified healthcare professional about your symptoms, before stopping or starting any medication, and before beginning a new supplement — particularly if you are pregnant, breastfeeding, immunocompromised or taking prescription medicines. If you have red flag symptoms such as rectal bleeding, unexplained weight loss or a persistent change in bowel habit, seek medical advice promptly rather than relying on a home test.