Understanding Faecal Calprotectin and Its Connection to Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) affects millions worldwide, causing chronic inflammation in the digestive tract. Diagnosing and monitoring IBD can be challenging due to overlapping symptoms with other gastrointestinal conditions. One tool that has gained attention for its usefulness in this area is faecal calprotectin. This protein marker found in stool samples offers valuable insights into intestinal inflammation. This post explores what faecal calprotectin is, how it relates to IBD, and why it matters for patients and healthcare providers.

What Is Faecal Calprotectin?

Faecal calprotectin is a protein released by white blood cells, specifically neutrophils, during inflammation. When the lining of the intestines becomes inflamed, neutrophils migrate to the affected area and release calprotectin, which then appears in the stool. Measuring the level of calprotectin in faeces provides a non-invasive way to detect inflammation in the gastrointestinal tract.

This protein is stable in stool samples for several days, making it practical for laboratory testing. Unlike blood tests that may reflect systemic inflammation, faecal calprotectin specifically indicates inflammation within the intestines.

How Faecal Calprotectin Is Measured

Testing for faecal calprotectin involves collecting a small stool sample, which is then analyzed in a laboratory. The results are usually reported in micrograms per gram (µg/g) of stool.

Typical reference ranges include:

• Less than 50 µg/g: Normal, indicating no significant intestinal inflammation

• 50 to 200 µg/g: Mild elevation, may require further investigation

• Above 200 µg/g: High likelihood of active inflammation, often seen in IBD

  
  

The test is simple, painless, and can be repeated over time to monitor disease activity.

The Role of Faecal Calprotectin in Diagnosing IBD

IBD primarily includes two conditions: Crohn’s disease and ulcerative colitis. Both cause inflammation in the digestive tract but differ in location and severity. Symptoms like abdominal pain, diarrhea, and weight loss overlap with other disorders such as irritable bowel syndrome (IBS), making diagnosis tricky.

Faecal calprotectin helps distinguish between IBD and non-inflammatory conditions like IBS. Elevated calprotectin levels strongly suggest inflammation, prompting further diagnostic procedures such as colonoscopy or imaging.

Example

A patient with chronic diarrhea and abdominal discomfort undergoes faecal calprotectin testing. The result shows a level of 350 µg/g, indicating significant inflammation. This finding leads the doctor to recommend a colonoscopy, which confirms Crohn’s disease. Without this test, the patient might have faced delayed diagnosis or unnecessary treatments.

Monitoring Disease Activity and Treatment Response

Once IBD is diagnosed, managing the disease involves regular monitoring to assess inflammation levels and treatment effectiveness. Faecal calprotectin serves as a useful biomarker for this purpose.

• Tracking flare-ups: Rising calprotectin levels can signal a flare before symptoms worsen.

• Evaluating treatment: Decreasing levels indicate that medication or lifestyle changes are reducing inflammation.

• Avoiding invasive tests: Regular stool tests can reduce the need for frequent colonoscopies, which are more invasive and costly.

  
  

Advantages of Using Faecal Calprotectin Testing

• Non-invasive: No need for blood draws or endoscopic procedures initially.

• Cost-effective: Less expensive than imaging or invasive tests.

• Specific to intestinal inflammation: More accurate than general inflammatory markers like C-reactive protein (CRP).

• Useful for all ages: Applicable for children and adults alike.

  
  
  
  

Limitations and Considerations

While faecal calprotectin is a valuable tool, it is not perfect. Some factors can affect results:

• Other causes of inflammation: Infections, colorectal cancer, or use of nonsteroidal anti-inflammatory drugs (NSAIDs) can raise calprotectin levels.

• Variability: Levels can fluctuate, so a single test may not provide a complete picture.

• Not a standalone diagnosis: It should be used alongside clinical evaluation and other tests.

  
  
  
  

Practical Tips for Patients and Healthcare Providers

• Patients should provide stool samples as instructed and avoid NSAIDs before testing to reduce false positives.

• Doctors can use faecal calprotectin to decide when to order more invasive tests or adjust treatment plans.

• Regular testing helps catch flare-ups early and improves long-term disease management.

  
  

Future Directions in Faecal Calprotectin Research

Research continues to explore how faecal calprotectin can be integrated with other biomarkers and imaging techniques to improve IBD care. Advances in home testing kits may soon allow patients to monitor their inflammation levels conveniently, leading to more personalized treatment.