Glossary · Markers and tests
Faecal calprotectin
In one sentence
Faecal calprotectin is a neutrophil protein measured in stool as a marker of inflammation of the intestinal lining. It helps distinguish inflammatory bowel disease from functional disorders such as irritable bowel syndrome.
Also known as: calprotectin · fecal calprotectin · stool calprotectin · calprotectina fecal
What is faecal calprotectin?
Calprotectin is a calcium- and zinc-binding protein found in large amounts inside neutrophils. When the intestinal lining becomes inflamed, neutrophils migrate into the gut wall and lumen, and calprotectin ends up in the stool. It remains stable at room temperature for several days, which makes it practical to measure in a small faecal sample.
It is a biomarker of intestinal inflammation rather than of any single disease: it signals that inflammation is present, not what is causing it.
What it is used for
Its main role is to help separate organic from functional disease. In 2013 the UK’s NICE (diagnostics guidance DG11) recommended faecal calprotectin in adults with recent-onset lower gastrointestinal symptoms, where cancer is not suspected, to help distinguish inflammatory bowel disease (IBD) from irritable bowel syndrome (IBS) before referral for specialist investigation. It is also used to:
- Support decisions on whether colonoscopy is needed.
- Monitor activity in established IBD (Crohn’s disease, ulcerative colitis).
- Track response to treatment over time.
How it is interpreted
Results are reported in µg/g of stool and obtained by immunoassay (ELISA) or immunoturbidimetry. As a rough guide, many laboratories regard values below 50 µg/g as normal, a grey zone of roughly 50 to 100-200 µg/g that may warrant a repeat test, and higher values as suggestive of organic inflammation. Cut-offs vary by assay and laboratory and are not directly interchangeable.
Calprotectin can also rise without IBD: infections, NSAIDs, diverticulitis, coeliac disease, polyps or tumours. Normal values are higher in young children. A low result makes significant inflammation unlikely, though it does not rule it out in every case.
Example
A GP sees a 28-year-old with three months of loose stools and abdominal pain but no red-flag features. Faecal calprotectin comes back at 25 µg/g. Together with a normal examination and blood tests, this makes IBD less likely and points towards a functional disorder, sparing the patient an immediate colonoscopy. Had the result been 450 µg/g, the next step would have been referral to gastroenterology.
Faecal calprotectin at Xenogene
Xenogene’s faecal calprotectin test quantifies the protein by ELISA or immunoturbidimetry in a stool sample collected with the laboratory kit, and the report compares the result with reference ranges. It can be combined with the gut microbiota and other functional markers in the integrated profiles. The test requires a prescription, and interpretation rests with the requesting professional.
Frequently asked questions
What else can raise calprotectin apart from IBD?
Gut infections, non-steroidal anti-inflammatory drugs (NSAIDs), diverticulitis, coeliac disease, polyps and colorectal cancer, among others. A raised result is therefore always read alongside the clinical picture and may be repeated or followed by further tests.
Does a high calprotectin mean cancer?
No. The most common reason for a raised level is inflammation of the gut lining from a range of causes. Calprotectin is not a bowel cancer screening test; the clinician decides whether further investigation such as colonoscopy is needed.
Should I stop ibuprofen before a calprotectin test?
NSAIDs can raise calprotectin. If you are taking them, the professional requesting the test will advise whether to pause them before collecting the sample; do not change medication on your own.
Related terms
- Biomarker
A biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, disease processes or responses to a therapeutic intervention. It may be a molecule, a genetic variant or an imaging finding.
- Low-grade inflammation
Low-grade inflammation is a mild, persistent, systemic inflammatory activation with no acute infection or injury to explain it. It is detected through modest rises in markers such as high-sensitivity CRP.
- Intestinal permeability
Intestinal permeability is how easily substances in the gut lumen cross the intestinal lining into the bloodstream. It is a normal, regulated property; increased permeability is associated with several diseases.
- Dysbiosis
Dysbiosis is a change in the composition or function of the microbiota away from what is considered compatible with health: loss of diversity, loss of beneficial microbes or overgrowth of others.
Educational content for healthcare professionals and the general public. It does not replace assessment by a healthcare professional: ordering and interpreting any test is the responsibility of the requesting clinician.
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