Faecal calprotectin in inflammatory bowel disease
What is faecal (fecal) calprotectin?
Calprotectin (or calpro) is a protein – a nutrient essential to life. When the intestines become inflamed it’s released in high levels that can be detected, outside the body, in faeces (stools).
Researchers have discovered that calpro is a biomarker, or measurable indicator, of inflammatory bowel disease (IBD) – both Crohn’s disease (CD) and ulcerative colitis (UC) – as well as other organic diseases.1 They are also looking at other biomarkers that may prove to be superior to calpro, or provide other useful information to help improve the management of IBD in the future. However, up to now, most of the focus of research in this area has been around the study of calpro.2
What is a faecal calprotectin test?
Although different testing technologies are available, ultimately they all do the same thing: measure the level of calprotectin in stool samples.
These tests mark an important breakthrough in the diagnosis and on-going management of IBD.
First, they can help doctors diagnose and distinguish IBD from non-inflammatory bowel diseases (eg irritable bowel syndrome (IBS)) between 70% and 100% of the time.1 (Researchers have found tests are slightly more accurate in the diagnosis of CD than UC.1)
IBS and IBD – getting the right diagnosis
Abdominal (tummy) pain, bloating, and diarrhoea or constipation are symptoms that may be caused by a number of different conditions, including IBD and IBS. Although IBS may cause great discomfort that affects the quality of someone’s life, people with IBS are generally not seriously unwell. Being able to quickly and accurately distinguish between IBS and IBD so that patients receive the most appropriate treatment is important.
People who have IBS/non-inflammatory bowel disease do not have as much calpro in their stools so the test can be useful to help diagnose and differentiate between these patients and those who have IBD, even though their symptoms may initially seem similar. Using a test with a clear measure of calpro levels, or one that indicates either a ‘positive’ or ‘negative’ for inflammation (a so-called qualitative measure), means that invasive, stressful, more timing consuming and riskier hospital investigations (such as colonoscopy) can be avoided for most people with IBS.1 A simple test that can differentiate between IBS and IBD at an early stage can also improve how patients are managed and ensure doctors refer people to the right specialist.
How can this test help manage the disease?
Non-invasive calpro testing is not only helping doctors diagnose IBD more accurately, it also has the potential to help them monitor how people are responding to treatment, as well as predicting its course and whether a patient may be at risk of a relapse/flare-up.
Mucosal healing (MH), or healing of the inflamed mucous lining of the bowel, has been associated with sustained clinical remission (a period when symptoms are less severe) in IBD, reduced rates of hospitalisation and a lower incidence of colorectal cancer.1 Not yet widespread in day to day clinical practice, calpro levels are now being assessed by researchers to understand whether they can be used to accurately assess the extent of MH following IBD treatment. In several clinical trials of different CD therapies, normalisation of calpro levels appeared to be a useful and reliable indirect measure for mucosal improvement and healing.1 Similar results have been found for UC. Normalisation of calpro has predicted sustained clinical remission when the signs and symptoms of the condition temporarily go away.1
Predict and prevent flare-ups
So far, the natural course of IBD has been unpredictable.3 If doctors could look into the future to predict and then take action that might prevent a flare-up, then this would be a big step forward in the management of IBD.
During the early stages of a relapse, when the clinical symptoms of IBD may not be obvious, faecal calpro can detect small increases of mucosal inflammation and so may identify patients at risk of a relapse. If patients at risk can be identified early by calpro testing then treatments can be altered to help prevent this.1
Calpro and e-Health
Calpro tests are suitable for home use and have been available since 2015 in some countries. This gives IBD patients more control, as well as having obvious practical benefits. The tests can be linked with Apps for smartphones (Android and iOS) that interpret the results using image processing and send results to your doctor. This allows active monitoring of your IBD without the need for regular outpatient appointments.
1: Lehmann FS, Burri E, Beglinger C. The role and utility of faecal markers in inflammatory bowel disease. Ther Adv Gastroenterol. 2015;8:23–36.
2: Walsham NE and Sherwood RA. Fecal calprotectin in inflammatory bowel disease. Clin Exp Gastroenterol. 2016; 9: 21–29. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734737/. Accessed 17 October 2016
3: Liverani E, Scaioli E, Digby R et al. How to predict clinical relapse in inflammatory bowel disease patients.
World J Gastroenterol 2016 January 21; 22(3): 1017-1033.
* Mucosa the membrane layer of the stomach