If you’ve had IBS for a while you might be considering getting a stool test, but should you bother? As an IBS nutritionist I sometimes use this tool to help my clients. 

What can a stool test tell you?

Stool testing can tell you

  • your levels of abundance of healthy and ‘bad’ bacteria
  • the health of the intestinal lining
  • whether you’ve got any infection in the gut
  • whether parasites or a yeast overgrowth are present
  • inflammation levels

It’s basically a sample of your poo that you put onto a test kit, and then post it off to be analysed. It takes around two to three weeks on average for the results to come back in. there are two approaches to the analysis

  • PCR analysis – looking at the DNA samples of the bacteria, parasites, fungi or viruses in your stool sample,
  • culture test – attempt to regrow the microbes and see what cultures appear.

The best stool tests now take both approaches to analysis.

Who can a stool test help?

Getting a picture of what is going on in the gut can help tweak a nutrition plan to feed up the healthy bacteria, or address over-abundance of less healthy bacteria.

Analysing the contents of your gut can be useful if you’ve got ongoing digestive issues that haven’t been resolved by simple dietary changes.

Sometimes changing your diet can have a massive impact on your symptoms. It might be removing a food type you’re intolerant to, or perhaps adding more fibre into your diet to improve constipation.

For some people, those simple dietary changes can really make a big difference, and a stool test doesn’t give additional information.

It can be really helpful to see more information if you’ve made dietary changes, but you still can’t see any improvements. Or if you’ve had gut issues for a really long time and you’ve been through various lifestyle changes and multiple GP visits, but you’re STILL dashing to the toilet 8 times a day, or unable to do up your trousers after a meal.

Looking at the bacterial balance in your gut, and health of the intestines can add another layer of information to the analysis. I use different labs to run these tests, but typically use Invivo, Regenerus or Genova.

Inflammation in the gut

One of the first things we look at is inflammation markers in the gut. When raised, these markers signify  the immune system is on high alert and is recruiting immune cells into the gut to deal with an infection, parasite or localised inflammation. All the different labs are slightly different in their approach to testing, but key markers are Calprotectin and Secretory IgA.

We can also see the health of the intestines through markers which highlight the integrity of the gut (e.g is it ‘leaky’), and analysis of the mucosal lining of the intestines.

Gut microbiome analysis

There are many different types of bacteria living the gut and we don’t yet have a clear picture of the optimal gut bacteria composition.

But that doesn’t mean a picture of your gut bacteria doesn’t tell us anything, it does help!

From ongoing research we do know that certain bacteria in high abundance may cause bloating and gas because they are more likely to produce hydrogen, or methane. These gasses are associated with symptoms like diarrhoea, bloating and pain.

A stool test can tell you which bacteria are abundant in the gut, and which are not present at all.

On it’s own this data doesn’t mean anything, but when we pair it with symptoms and health history it becomes very useful. 

We also see that certain diets are associated with certain bacterial patterns.  For example people who’ve been on the low fodmap diet for a long time will actually have a very low microbial diversity because they have been removing all those fermentable carbohydrates. This will starve out all the bacteria which is why this diet shouldn’t be followed long term.

Food breakdown

Your stool test will show you how fats are digested and the way that protein is digested.  Maldigestion of protein or fats can lead to fermenting and bloating, in the colon.

Stool tests can highlight infections

Most stool tests will highlight bacteria infections, for example, Helicobacter pylori can cause stomach ulcers when it is left untreated, and can be linked to symptoms such as acid indigestion and reflux.



Identifying yeast overgrowth and parasites

In the stool results test we will look at overgrowth of yeast profiles, with some of the stool tests as well they can actually show you with the type of Candida that you’ve got, and which type of remedy would be best.

It might feel like quite a scary thought to think there are parasites inside the gut, but it is also fairly common. Not everyone will react to evidence of parasites in their body. For example Blastocystis hominis and Dientamoeba fragilis are only pathogenic in some individuals.

You may have picked a parasite up through contact with an animal, nappy changing, or exposure to dirty water.

Parasites could be in the gut at a low level for a long time without symptoms, but then if you get rundown, or have anther infection you’re fighting off they can take a bigger hold on your system. If you’ve had treatment in the past for parasitic infection you might still have a low level that could be causing issues, even years later.

How do you get a stool test?

Your GP tests can run some stool tests on the NHS if they suspect a parasitic or bacterial infection. These tests will not provide a detailed bacterial analysis described above, they will just help check you for parasites and key infections.

If you’d like to run a private stool test get in touch to ask me about how to do it.

How much do stool tests cost?

They aren’t cheap, but can be insightful for those clients who need additional data. Most high quality tests are in the region of £250-370. If I organise a test for you it also comes with my time to analyse the results and provide you with some insight into what is going on. Contact me to ask about a stool test for IBS – info@goodnessme-nutrition.com


Hi I'm Anna Mapson, registered Nutritional Therapist.

I help people with IBS and SIBO get control of unpredictable gut symptoms to find long term relief from painful and embarrassing IBS without restrictive dieting.

I can help you to:

  • understand your digestion better, so you recognise your triggers
  • eat a well balanced diet, with tasty meals that are simple to prepare
  • develop better digestion and more energy

Find more about my 3 month 1:1 Gut Reset programme

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