Kristinsson et al, investigated fecal calprotectin levels in patients with colorectal carcinoma and found that the median calprotectin level in these patients was higher than in controls. Moreover, levels fell significantly following surgical resection. Fecal calprotectin levels in subjects with colorectal cancer do not correlate with tumor stage so, this allow for earlier detection of neoplasms. A direct comparison of Fecal occult blood (FOB) to fecal calprotectin in detecting colorectal carcinomas and adenomas has shown calprotectin to be more sensitive (79% vs.
43%) but less specific (72% vs. 92%). Fecal calprotectin is elevated in cases of inflammatory bowel disease (IBD). In ulcerative colitis (UC) fecal calprotectin is elevated in quiescent disease compared with healthy controls and correlates with endoscopic and histological grading of disease severity.
In subjects with IBD who are in remission, fecal calprotectin levels can predict relapse rate over the following 12 months. Fecal calprotectin has a sensitivity of 96% in discriminating between normal subjects and those known to have Crohn’s disease (CD). As a diagnostic test, fecal calprotectin shows better discrimination than C-reactive protein and erythrocyte sedimentation rate in distinguishing between patients with irritable bowel syndrome (IBS) and Crohn’s disease. Fecal calprotectin has been shown to have a role in monitoring NSAID-induced damage. Administration of NSAID causes significant increases in fecal calprotectin within 7 days and this is correlated to endoscopic scores of mucosal damage. Tibble et al, compared fecal calprotectin with 4-day fecal excretion of indium-labeled white cells in subjects on NSAID. There was significant correlation between the tests. Fecal calprotectin has the advantage of not exposing subjects to radioactivity and not requiring a 4day fecal collection.
Recently, Shah et al, used calprotectin determinations to show that selective inhibitors of cyclooxygenase (COX-2) do not increase fecal excretion of calprotectin as compared with a non-selective NSAID. This finding suggests that COX-2 inhibitors may be safer than traditionally used NSAID.