Fecal Calprotectin Test

The fecal calprotectin test is a diagnostic tool used to detect inflammation in the gastrointestinal tract, particularly in the intestines. It measures the level of calprotectin, a protein found in stool, which is a marker of intestinal inflammation.

What is Calprotectin?

Calprotectin is a protein that is found in the stool and is produced by white blood cells called neutrophils. It is a stable protein that resists degradation by enzymes in the gut, making it an ideal marker for detecting intestinal inflammation.

Purpose of the Test

The fecal calprotectin test is used to:

• Differentiate between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS)
• Monitor the activity of IBD, such as Crohn's disease and ulcerative colitis
• Assess the effectiveness of treatment for IBD
• Screen for intestinal inflammation in patients with symptoms such as abdominal pain, diarrhea, or weight loss

How is the Test Performed?

The test involves collecting a stool sample from the patient, which is then sent to a laboratory for analysis. The sample is tested for the presence and quantity of calprotectin using an enzyme-linked immunosorbent assay (ELISA) or other immunoassay techniques.

Interpretation of Results

The results of the fecal calprotectin test are typically reported as a concentration of calprotectin in micrograms per gram of stool (μg/g). The normal range for calprotectin is generally considered to be:

• < 50 μg/g: Normal, no inflammation detected
• 50-120 μg/g: Borderline, may indicate mild inflammation or other conditions
• > 120 μg/g: Abnormal, indicates significant intestinal inflammation

Clinical Significance

A high level of calprotectin in the stool is associated with an increased risk of IBD, particularly Crohn's disease and ulcerative colitis. The test can also be used to monitor the effectiveness of treatment for these conditions and to assess the risk of relapse.

Limitations and Precautions

The fecal calprotectin test is not foolproof and may have some limitations, including:

• False-negative results can occur in patients with mild or early inflammation
• False-positive results can occur in patients with other conditions, such as infections or gastrointestinal bleeding
• The test may not distinguish between different types of IBD or other inflammatory conditions

Conclusion

The fecal calprotectin test is a useful diagnostic tool for detecting intestinal inflammation and monitoring the activity of IBD. While it has some limitations, it can provide valuable information to help guide diagnosis and treatment decisions.