From the Guidelines
Fecal calprotectin is a protein found in stool that serves as a biomarker for intestinal inflammation, with levels below 50 micrograms per gram of stool typically indicating no inflammation, and higher levels suggesting potential inflammation, as supported by recent guidelines 1.
Definition and Purpose
Fecal calprotectin is measured through a simple stool test that detects the presence of calprotectin, a protein released by white blood cells called neutrophils when there is inflammation in the intestines. This test is particularly useful for diagnosing and monitoring inflammatory bowel diseases (IBD) like Crohn's disease and ulcerative colitis, helping to distinguish these conditions from non-inflammatory disorders such as irritable bowel syndrome (IBS).
Clinical Application
The test is non-invasive and can help reduce the need for more invasive procedures like colonoscopies. Doctors often use fecal calprotectin to assess disease activity, monitor treatment effectiveness, and predict potential disease flares in patients with IBD.
Interpretation of Results
According to the most recent guidelines, a calprotectin cut-off of 50 μg/g has the best sensitivity to detect endoscopically active disease, with specificity performing best at levels >100 μg/g 1. However, a more recent study suggests that calprotectin levels <150 ± 50 mg/g may reliably rule out active inflammation, although this has low certainty of evidence 1.
Key Points
- Fecal calprotectin is a biomarker for intestinal inflammation
- Levels below 50 micrograms per gram of stool typically indicate no inflammation
- Higher levels suggest potential inflammation
- The test is non-invasive and can help reduce the need for colonoscopies
- Fecal calprotectin is used to assess disease activity, monitor treatment effectiveness, and predict potential disease flares in patients with IBD.
From the Research
Definition and Purpose of Fecal Calprotectin
- Fecal calprotectin is a biomarker used in the evaluation of inflammatory bowel disease (IBD) 2, 3, 4, 5.
- It is a calcium-containing protein released into the lumen and excreted in feces during acute and chronic inflammation 3, 4.
- Fecal calprotectin is used as a noninvasive test for detecting intestinal inflammation, and its utility in differentiating IBD from functional conditions is well documented 3, 5.
Clinical Applications of Fecal Calprotectin
- Fecal calprotectin is used to predict the need for escalation of therapy in established IBD 2.
- It is also used to monitor response to therapy and to determine treatment in IBD 2, 3, 5.
- Fecal calprotectin correlates closely with endoscopic activity of IBD, and a low concentration predicts persistence of clinical remission 5.
Characteristics and Measurement of Fecal Calprotectin
- Fecal calprotectin is a simple, reliable, and low-cost test for detecting intestinal inflammation 5.
- It is measured by ELISA, and its concentration is higher in feces than in plasma 4.
- Fecal calprotectin levels are significantly increased in patients with IBD, and it can be regarded as a surrogate marker of neutrophils influx into the bowel lumen 4.
Limitations and Additional Considerations
- Fecal calprotectin elevation can be observed in other gastrointestinal pathological conditions, including infective colitis, microscopic colitis, eosinophilic colitis, adenomas, and colorectal cancer 6.
- Individual, environmental, and method-related factors can affect fecal calprotectin measurement and its clinical interpretation 6.