Faecal Calprotectin Tests: The Ultimate Patient Guide (2021)

Want to learn more about testing for faecal calprotectin? You’ve come to the right place.

This article explains what faecal calprotectin is, why you might want to know your faecal calprotectin level, and how you go about testing it. For a general introduction to faecal calprotectin, head over to Faecal Calprotectin Made Easy (2020).


What is a faecal calprotectin test?
What does a faecal calprotectin test actually test for?
Faecal calprotectin testing on the NHS
Faecal calprotectin test results
How much does a private FC test cost?
How long do faecal calprotectin test results take?

Speak to a gut health expert.


What is a faecal calprotectin test?

A faecal calprotectin test looks at the level of inflammation in your intestines.

Inflammatory bowel disease (IBD) involves more inflammatory activity than functional digestive disorders such as irritable bowel syndrome (IBS). That’s why a faecal calprotectin test is often used to distinguish between IBD (including Crohn’s disease and ulcerative colitis) and irritable bowel syndrome (IBS) [1].

A faecal calprotectin test alone cannot diagnose IBD—but it can show you whether further tests for IBD (such as a colonoscopy) are necessary.

If your GP suspects that your digestive symptoms are down to IBD, they can order a faecal calprotectin test for you. But up to 20% of the population experience digestive symptoms [2], and not all of them are referred for a faecal calprotectin test. That’s why it’s useful to have the option to test for faecal calprotectin as part of a comprehensive, at-home stool test.

To take the test, you simply collect some of your stool (poo). This involves placing a tissue cover over your toilet bowel, and passing stools as normal. You then collect a small sample of your stools using a purposefully designed spoon and test tube, and post it off to a lab.

Lab technicians use a special technology called the ELISA method to measure the amount of faecal calprotectin in your stool sample. The amount measured is tiny—usually micrograms of calprotectin per gram of stool— but it’s enough to indicate the level of inflammation in your intestines.

Faecal calprotectin levels can be affected by stool consistency [3], so to get the most accurate result possible, it’s important you prepare for the stool test. You can read more about this—including what to do—in Stool Testing – The Ultimate In-Depth Guide (2020).

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What does a faecal calprotectin test actually test for?

Faecal calprotectin is a substance released by white blood cells.

When there is inflammation in your intestines, white blood cells migrate to the affected area as part of the immune response. More inflammation = more white blood cells = more faecal calprotectin [4].

Faecal calprotectin hangs around in your stools for up to seven days, which makes it easy to measure in a stool sample using the ELISA method. That’s why it’s often a called a ‘poo pathology test’.

Compared to a colonoscopy (which involves inserting a tube with a camera into your bottom), taking a stool test for faecal calprotectin is a simple, non-invasive way to get insight into the degree of recent inflammatory activity in your intestines.

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Faecal calprotectin testing on the NHS

Faecal calprotectin testing has been used regularly in NHS practice since NICE approved it as a screening tool in 2013 [5].

Doctors most often order a faecal calprotectin test if a person has severe digestive symptoms and bowel cancer has already been ruled out. In those instances, a person is often suspected to have a form of IBD.

A faecal calprotectin test alone is not enough to diagnose IBD. A high faecal calprotectin score indicates that the patient should have a colonoscopy to check for ulcerative colitis or Crohn’s disease—which can then be diagnosed. As faecal calprotectin tests accurately indicate IBD more than 90% of the time [6], it’s saved thousands of people from having unnecessary camera-up-bottom experiences.

But not everyone who has IBS-like symptoms will be referred for a faecal calprotectin test, and not all intestinal inflammation leads to digestive symptoms. That means you can still have intestinal inflammation without suspected IBD. There’s no standard IBS test either.

If your GP doesn’t order a faecal calprotectin test for you, you still have the option to take a private, at-home stool test.

Why test for Faecal_Calprotectin

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Faecal calprotectin test results

Faecal calprotectin is measured as mcg/g, so the results come back as a numeric value. The cut-off points vary in the scientific literature, but a general guide is:

  • A level under 50 is considered to be ‘normal’.
  • A level between 50 and 100, coupled with digestive symptoms, means IBS is likely.
  • A level between 100 and 250 is inconclusive. Your test may be falsely high, which means it’s wise to retest after a couple of weeks.
  • A level over 250 means IBD is likely. You should be referred for further tests.

Bear in mind that normal can be different for everyone, and levels fluctuate [7]. Substances like over-the-counter painkillers can also lead to a falsely high result. If you’re opting for a private test, make sure you choose one that asks you about your age and symptoms, as these are relevant too.

You can read more about the significance of different faecal calprotectin levels in Faecal Calprotectin Made Easy (2020).

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How much does a private Faecal Calprotectin test cost?

A private, standalone faecal calprotectin test costs around £100. This will give you a faecal calprotectin ‘score’, but it will tell you nothing else about your gut health.

A comprehensive gut health test costs around £300. This not only looks at faecal calprotectin, but it also looks at other biomarkers for bacteria, yeasts, parasites, immune activity and digestive function.

If you can afford to spend a little more, it’s worth going for the second option. A comprehensive gut test is more helpful than a single faecal calprotectin test because it gives an overview of your gut health as a whole—including insight into possible reasons for inflammation.

Whichever test you choose, it’s important to realise it can’t give you a diagnosis. What it can do is give you useful data to discuss with your doctor or healthcare provider. A good test report will also suggest dietary and lifestyle habits to help improve your gut health as a whole.

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How long do faecal calprotectin test results take?

Turnaround times for private faecal calprotectin tests vary, but it usually takes less than a month.

Here’s how the process works at Healthpath:

  1. Order your test online.
  2. Receive the test kit within 3 working days.
  3. Make sure you eat your normal diet for at least a week, and then take the test.
  4. Post your sample back to the lab on the same day.
  5. Receive your results within 2 weeks.

From when you click ‘Order’ to when you get your results, you should allow for a maximum of 3 weeks—though it’s often quicker.

Faecal calprotectin test turnaround times vary on the NHS too. After you’ve returned your sample, your doctor will receive the results within 5–7 days. You usually have to book a GP appointment to discuss your results. According to a recent survey, the average waiting time for a GP appointment is 2 weeks, though it can take up to a month [8].

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Speak to a gut health expert.



A faecal calprotectin test looks at the level of inflammation in your intestines.

The NHS uses faecal calprotectin tests as a screening tool for inflammatory bowel disease (IBD). Faecal calprotectin is also included in private, comprehensive gut health tests.

A faecal calprotectin test is an easy, non-invasive way to see if there’s any inflammatory activity in your intestines. This is helpful if you know you have IBD, but it’s also useful if you have other digestive or IBS-like symptoms. Even if you have no symptoms, it can be insightful.

A faecal calprotectin test does not diagnose anything, but it can give you useful data to discuss with your doctor. Paired with other biomarkers, it can also show you if you need to take steps to support your gut health.

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Fiona Lawson BA (Hons) DipCNM mBANT is a Registered Nutritional Therapist and health writer. She is a member of the Complementary and Natural Healthcare Council (CNHC) and the Institute for Functional Medicine (IFM). As Content Director of Healthpath, Fiona is on a mission to help people take charge of their own health. Read more about Fiona on her practitioner page.

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1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4567401/
2 https://www.nice.org.uk/guidance/cg61/chapter/Introduction
3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6366951/
4 https://www.ncbi.nlm.nih.gov/pubmed/16474109
5 https://www.nice.org.uk/guidance/dg11
6 https://www.bmj.com/content/341/bmj.c3369
7 https://academic.oup.com/ecco-jcc/article-abstract/13/11/1372/5427075?redirectedFrom=fulltext
8 http://www.pulsetoday.co.uk/home/finance-and-practice-life-news/average-gp-waiting-times-exceed-two-weeks-for-first-time-ever/20039156.article
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