Gut
Calprotectine
An inflammation protein in the stool; with bowel symptoms, helps distinguish bowel inflammation from irritable bowel.
Everything about this testWhat it measures
Calprotectin is a protein from white blood cells (neutrophil granulocytes). When the bowel wall is inflamed, many of these cells end up in the bowel and calprotectin gets into the stool. The test measures how much calprotectin is in a portion of stool. The more inflammation in the bowel, the higher the value.
- Chronic bowel inflammation (inflammatory bowel disease, IBD), such as Crohn's disease and ulcerative colitis
- Distinction between bowel inflammation and irritable bowel syndrome (IBS), with recurring diarrhea
- Measure of the activity of a known chronic bowel inflammation
High
A raised calprotectin points to inflammation in the gastrointestinal tract. This can fit a chronic bowel inflammation such as Crohn's disease or ulcerative colitis, especially with symptoms such as long-lasting diarrhea, blood or mucus in the stool and weight loss. A raised value also occurs with a bowel infection, with use of anti-inflammatory painkillers (NSAIDs such as ibuprofen or diclofenac) and with celiac disease. Rarely: a bowel polyp or bowel cancer. According to the guideline, a value above 100 micrograms per gram of stool is positive, and 50 to 100 is a gray area.
Low
A low value (below 50 micrograms per gram of stool) makes chronic bowel inflammation very unlikely. With recurring abdominal pain and changing stools, this fits irritable bowel syndrome more, a condition that is unpleasant but not dangerous and in which the bowel looks normal. A low value does not rule out other causes of bowel symptoms, such as celiac disease. With very watery stool, the value can be falsely low.
If your result is abnormal
With a value above 100 micrograms per gram, the GP refers to a gastroenterologist, according to the guideline; with a value between 50 and 100, the GP first consults the gastroenterologist. With a low value, an endoscopy of the bowel is usually not needed.
Reliability
According to the multidisciplinary guideline on irritable bowel syndrome by GPs (NHG) and gastroenterologists, the calprotectin test is mainly good at ruling out chronic bowel inflammation: in general practice, almost everyone with a negative result does not have bowel inflammation. A positive result is less certain; some people with a raised value turn out not to have a bowel disease on further testing. The guideline uses below 50 as negative, 50 to 100 as a gray area and above 100 micrograms per gram as positive.
Limitations
- Anti-inflammatory painkillers (NSAIDs) and a bowel infection can raise the value without chronic bowel inflammation.
- With very watery stool, the value can be falsely low.
- The various calprotectin tests differ greatly; cut-off and reference values differ between laboratories.
- Outside general practice, in groups with many bowel diseases, the test is less reliable for ruling out inflammation.
How common is this
Irritable bowel syndrome is common: according to the guideline, it affects about 4 in 100 adults in the Netherlands (by the strictest criteria), more often women and at a younger age. Chronic bowel inflammations such as Crohn's disease and ulcerative colitis are much rarer. The guideline gives no Dutch figure for these.
Who is this useful for
According to the guideline, useful with recurring diarrhea that has been present for 3 to 6 months and a raised chance of chronic bowel inflammation, for example with a parent, brother, sister or child with Crohn's disease or ulcerative colitis. Also used in people with a known bowel inflammation to monitor its activity. In people without bowel symptoms, the test is not useful. With blood in the stool, unexplained weight loss or new bowel symptoms starting after age 50, the test is no substitute for an examination by the GP.
Downsides and risks
- A slightly raised value, for example due to a painkiller or a passing infection, can lead to unnecessary worry or an endoscopy of the bowel.
- A low value can give false reassurance about other causes of bowel symptoms that the test does not measure.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results