About Calprotectin

Calprotectin is a protein biomarker that is present in the faeces when intestinal inflammation occurs. Faecal calprotectin testing is helping to improve patient care and save money for the NHS. It prevents the need for unnecessary endoscopy procedures on many patients by screening out those with Irritable Bowel Syndrome (IBS).

The symptoms of functional disorders such as IBS and organic Inflammatory Intestinal Disease (IBD) can be very similar in presentation but are two very different medical conditions.

Historically, clinical gastroenterologists have had to use invasive endoscopy to differentially diagnose between these conditions. NICE [DG11] now recommends the use of faecal calprotectin analysis, as a first-line test, in patients presenting with gastrointestinal symptoms indicative of IBS or IBD. The test can rule out IBD and avoid the need for IBS patients to undergo endoscopy. This prevents patient stress, shortens waiting lists and cuts costs.

Calprotectin is also shown to be of value in the ongoing assessment of known IBD patients, with the biomarker concentration reflecting mucosal healing or potential relapse.

Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease is a group of inflammatory conditions of the colon and small intestine. The major types of IBD are Crohn’s disease and Ulcerative Colitis.

Read more about IBD

Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome is a common condition of the digestive system. It can often cause bouts of stomach cramps, bloating, diarrhoea and constipation.

Read more about IBS

What is Faecal Calprotectin?

Calprotectin is:

  • A heterodimer of calcium binding proteins (MRP8/14)
  • Belongs to the S-100 protein family
  • Released from Polymorphic nucleated cells and monocytes upon cellular activation (or death) at sites of active inflammation
  • Can account for up to 60% of cytosolic protein in macrophages and neutrophil granulocytes
  • Induces apoptosis
  • Present in plasma and faeces
  • Highly stable in faecal samples (up to 7 days in stool samples are kept at RT).
  • Resists enzymatic degradation

Why measure Calprotectin?

Measurement of faecal Calprotectin is considered a reliable indicator of inflammation and numerous studies show that while faecal Calprotectin concentrations are significantly elevated in patients with IBD, patients suffering from IBS do not have increased Calprotectin levels. Such increased levels are shown to correlate well with both endoscopic and histological assessment of disease activity.

The NHS Centre for Evidence-based Purchasing has conducted several reviews on calprotectin testing and its use in differentiating IBS and IBD. These reports conclude that using calprotectin assays supports improvements in patient management and offers substantial cost savings.

Faecal Calprotectin is used to help differentiate between IBS and IBD. It is also used to assess the efficacy of treatment and predict the risk of flare-ups in IBD patients. Calprotectin levels are raised in patients with IBD and below 50µg/g in patients with IBS.

Children often have slightly higher Calprotectin levels than adults.

Measuring Calprotectin in the Lab Measuring Calprotectin at Point of Care

Calprotectin and Mucosal Healing

The treatment aim in IBD patients is clinical remission. Mucosal healing is associated with sustained clinical remission along with reduced rates of hospitalisation and surgical resection and identifying patients likely to relapse enables their therapy to be adjusted accordingly.

Determining relapse in patients presenting with no blood in faeces prevents the need for sigmoidoscopy and enables treatment to be started earlier.

Calprotectin levels predict clinical relapse with a 90% sensitivity and 83% specificity.

Tibble et al demonstrated that amongst patients with IBD in remission, 90% with a high faecal Calprotectin level had relapsed within a year, whilst only 10% of those with a low faecal Calprotectin level relapsed within the same period.

View all Calprotectin Literature