Faecal Calprotectin Made Easy (2020)

Faecal calprotectin (also known as fecal calprotectin) is a biomarker included in in-depth gut health tests.

This article explains what faecal calprotectin is and why it’s useful. To learn more about testing for faecal calprotectin, head over to Faecal Calprotectin Tests: Ultimate Patient Guide (2020).


What is faecal calprotectin?
Faecal calprotectin levels and the NHS
Faecal calprotectin levels
Causes of raised faecal calprotectin
Faecal calprotectin levels in cancer
Faecal calprotectin levels in children

What is faecal calprotectin?

Faecal calprotectin is a marker of inflammation in the gut. It is often used to distinguish inflammatory bowel disease (IBD) from irritable bowel syndrome (IBS).

When there is inflammation in the intestines, white blood cells migrate to the affected area to help fight it off. As part of the immune response, these white blood release special chemicals—one of which is faecal calprotectin.

Faecal calprotectin remains stable for about a week, which means it can easily be detected in stools (poo). [1] Generally speaking, more white blood cell activity = more inflammation. This means the higher your faecal calprotectin score, the more inflammation in your intestines and the more likely you are to have IBD.

IBD can be Crohn’s disease or ulcerative colitis. IBD is more serious than IBS—but without a test it can be hard to know which one you have, as IBD symptoms and IBS symptoms often overlap.

Symptoms that can arise in both IBD and IBS include:

  • Abdominal pain or cramps
  • Swelling in the tummy
  • Diarrhoea
  • Mucous in stools
  • Fatigue

A faecal calprotectin test can help you understand the degree of inflammation in your intestines. This can show you whether you’re symptoms are likely down to IBS, or whether you need to see your doctor to investigate IBD.

If you already know you have IBD (either Crohn’s disease or ulcerative colitis), regularly re-testing your faecal calprotectin score can help you to see how well your gut is healing. [2] It may even help to predict relapse in symptoms. [3]

The only thing faecal calprotectin can’t do is differentiate between Crohn’s disease and ulcerative colitis. To know which form of IBD you have, you’d need to have a colonoscopy.

In the UK, you can check your faecal calprotectin levels if your GP refers you for a test, or you test it privately with an at-home stool test.

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Learn more about your gut health. Talk to our experts.


Faecal calprotectin levels and the NHS

The National Institute for Health and Care Excellence (NICE) approved faecal calprotectin as a screening tool for IBD in 2013, which means it’s regularly used by the NHS. [4]

Before this, patients had to endure an invasive colonoscopy to check if their IBS-like symptoms were down to the more severe IBD. Now, as long as cancer has already been ruled out, doctors tend to check faecal calprotectin scores in a simple stool test first—and then decide if further tests for IBD are necessary.

But not all people who suffer from IBS will be automatically referred for a faecal calprotectin test. That’s why it’s useful to have an option to test faecal calprotectin privately.

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Faecal calprotectin levels

As faecal calprotectin levels show the degree of inflammation in your intestines, the different levels mean you need to take different actions.

The unit of measurement for faecal calprotectin is mcg/g, meaning the test detects micrograms of faecal calprotectin per gram of stool. The amounts measured may be tiny, but they’re significant: [5]

    • A level under 50 is considered to be ‘normal’ and means you don’t need to take any special action.
    • A level between 50 and 100, coupled with digestive symptoms, means IBS is likely. You should take steps to address your IBS, and visit your GP if symptoms persist after eight weeks.
    • A level between 100 and 250 is inconclusive. Your test may be falsely high (see ‘Causes of raised faecal calprotectin’ below), which means it’s wise to retest after a couple of weeks. If a second test is high, you need to speak to your doctor as soon as possible.
    • A level over 250 means IBD is likely. You should speak to your doctor straight away to be referred for further tests

Bear in mind that we’re all biochemically unique, so ‘normal’ faecal calprotectin levels vary from person to person. In the same person, levels can also fluctuate day-to-day. [6]

If you’ve never suffered from digestive symptoms, it’s expected that your faecal calprotectin score will be low. But levels don’t always correlate with symptoms, and it’s still important that speak to your GP if your levels aren’t normal.

Why test for Faecal_Calprotectin

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Causes of raised faecal calprotectin

Although faecal calprotectin levels have been found to correlate well with colonoscopy findings of IBD, there is still a small chance of getting a falsely high score (known as a ‘false positive’).

Substances that can raise faecal calprotectin levels include:

  • Non-steroidal anti-inflammatory drugs (NSAIDs).[7] These include aspirin and ibuprofen.
  • Proton pump inhibitors (PPIs). [8]These are medications commonly used for heartburn or acid reflux.

If you’re taking either of these medications, your faecal calprotectin score may not be accurate. But you must never stop a medication to take a test. Speak to your doctor first.

Conditions other than IBD can also lead to raised faecal calprotectin levels. These include:

  • Pancreatitis [9]
  • Liver cirrhosis [10]
  • Gut infection [11]

If you suspect you have pancreatitis (an inflamed pancreas) or liver cirrhosis (scarring of the liver), it’s important you’re monitored by your doctor. If you want to explore whether you have a gut infection, you can take a gut microbiome test.

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Faecal calprotectin levels in cancer

There’s some evidence that colorectal cancer (also known as bowel cancer) can also lead to elevated levels of faecal calprotectin [12].

But faecal calprotectin alone should not be used to assess for colorectal cancer. This is because there are much better and much more accurate screening tools for colorectal cancer available.

One of these screening tools is the presence of blood in the stools. In the UK, every person aged between 60 and 74 is sent a kit every two years to test for blood in their stools. You can read more about this in Stool Testing – The Ultimate In-Depth Guide.

Healthpath’s Advanced Gut Health Test looks for both faecal calprotectin and blood in stools. This test can’t give you a diagnosis, but it can provide you with data to discuss with your doctor.

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Learn more about your gut health. Talk to our experts.


Faecal calprotectin levels in children

Children and teenagers can also be tested for faecal calprotectin, but the test may be less accurate. The chance of a false positive faecal calprotectin score in adults is 4%, while in children and teenagers it’s 24%. [13]

Although researchers don’t know the exact reason for this discrepancy, it may be because stool samples from very young children tend to be taken from nappies—making them less viable. This may skew study results.

There are other differences too. Faecal calprotectin levels tend to be naturally higher in children. [14]A higher faecal calprotectin level can also be associated with Coeliac disease and food allergy in children, while this association isn’t as strong in adults. [15],[16]

So, what does this mean for your or your child?

It’s still worthwhile to test faecal calprotectin, and doctors will order it if they suspect IBD in a child. If you’re ordering a private test that includes faecal calprotectin, it’s worth checking that—like in Healthpath’s reports—the interpretation of the results takes into account the subject’s age and symptoms. After all, data without context is meaningless.
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Faecal calprotectin is a marker of inflammation in the gut.

The main role of faecal calprotectin is to differentiate between cases of irritable bowel syndrome (IBS) and the more serious inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis. Even if you don’t have IBS or IBD, it can still show if there’s inflammation in your gut.

Digestive symptoms don’t always correlate with the degree of inflammation, so the only way to know your faecal calprotectin level is to test for it. Your NHS doctor can refer you for a faecal calprotectin test, or it can be ordered privately as part of a comprehensive gut health test.

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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/pubmed/27668453
2 https://www.ncbi.nlm.nih.gov/pubmed/15513345
3 https://www.ncbi.nlm.nih.gov/pubmed/10889150
4 https://www.nice.org.uk/guidance/dg11
5 https://www.nice.org.uk/guidance/dg11/resources/primary-care-guidelines-york-teaching-hospital-pdf-4535195223
6 https://academic.oup.com/ecco-jcc/article-abstract/13/11/1372/5427075?redirectedFrom=fulltext
7 https://www.ncbi.nlm.nih.gov/pubmed/10446103
8 https://www.ncbi.nlm.nih.gov/pubmed/12702920
9 https://www.ncbi.nlm.nih.gov/pubmed/17876545
10 https://www.ncbi.nlm.nih.gov/pubmed/22093455
11 https://www.ncbi.nlm.nih.gov/pubmed/19028207
12 https://www.ncbi.nlm.nih.gov/pubmed/8303210
13 https://www.bmj.com/content/341/bmj.c3369
14 https://www.ncbi.nlm.nih.gov/pubmed/11964964
15 https://www.ncbi.nlm.nih.gov/pubmed/23161294
16 https://www.ncbi.nlm.nih.gov/pubmed/12765980
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