Calprotectin is a major calcium-binding protein found predominantly in neutrophils with antimicrobial and antiproliferative activities. When inflammatory processes occur, calprotectin is released due to the degranulation of neutrophil granulocytes. In bowel inflammation, calprotectin may be detected in the stool. An increased calprotectin concentration in stool is the direct consequence of neutrophil degranulation due to mucosal damage. Calprotectin levels are higher in feces than in plasma and significantly elevated in IBD patients (ulcerative colitis and Crohn disease) and in indeterminate colitis. Similar sensitivity and specificity as of fecal lactoferrin assay.
Normal range: negative.
Use
Diagnose inflammatory bowel disease (IBD), including Crohn disease and ulcerative colitis
Differentiate IBD from irritable bowel syndrome (IBS)
Monitor IBD activity and predict relapse
Interpretation
Increased In
Screening for inflammation in patients presenting with abdominal pain and diarrhea
Distinguish patients with active IBD from noninflammatory IBS
Monitor IBD activity
Decreased In
NA
Limitations
Presence of GI infections and colorectal cancer may falsely elevate levels.
Does not differentiate among inflammatory bowel pathologies.
False negatives are more common in children and teenagers than in adults.
Fecal calprotectin levels increase after use of nonsteroidal anti-inflammatory drugs, that levels may change with age.
Bleeding (e.g., nasal or menstrual) may cause an elevated fecal calprotectin level.