Calprotectin (Faecal)

Faecal calprotectin is a protein released into the gut when there is inflammation in the intestines. Measuring its level in a stool sample provides a useful, non-invasive way to detect and monitor inflammation in the bowel. Because levels rise specifically with intestinal inflammation, it is a helpful marker for distinguishing inflammatory bowel conditions from non-inflammatory ones.

What it can help assess

• Detecting bowel inflammation: raised levels suggest inflammation in the intestines that may need further investigation
• Distinguishing inflammatory from non-inflammatory conditions: it helps tell apart inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis, from conditions like irritable bowel syndrome (IBS), which does not cause inflammation
• Monitoring known inflammatory bowel disease: it is widely used to track disease activity and response to treatment over time

An important note on interpretation

Faecal calprotectin indicates the presence of inflammation but does not identify its exact cause. Levels can be raised by a range of conditions beyond IBD, including gut infections, certain medications such as anti-inflammatory painkillers, and other bowel conditions. A raised result usually means further investigation is needed rather than giving a diagnosis on its own, and results are always interpreted alongside your symptoms and other clinical information.

Why it matters

Faecal calprotectin is a valuable first-line test for anyone with ongoing digestive symptoms, as it helps guide whether further investigation, such as a colonoscopy, is needed. It offers a simple, non-invasive way to check for bowel inflammation, and any raised or abnormal result should be discussed with your GP or specialist to determine the appropriate next steps.