A simple method for assessing intestinal inflammation in Crohn's disease

Background and aims-Assessing the presence and degree of intestinal inflamm ation objectively, simply, and reliably is a significant problem in gastroe nterology. We assessed faecal excretion of calprotectin, a stable neutrophi l specific marker, as an index of intestinal inflammation and its potential use as a screening test to discriminate between patients with Crohn's dise ase and those with irritable bowel syndrome. Methods-The validity of faecal calprotectin as a marker of intestinal infla mmation was assessed in 22 patients with Crohn's disease (35 studies) by co mparing faecal excretions and concentrations using four day faecal excretio n of (111)indium white cells. A cross sectional study assessed the sensitiv ity of faecal calprotectin concentration for the detection of established C rohn's disease (n=116). A prospective study assessed the value of faecal ca lprotectin in discriminating between patients with Crohn's disease and irri table bowel syndrome in 220 patients referred to a gastroenterology clinic. Results-Four day faecal excretion of (111)indium (median 8.7%; 95% confiden ce interval (CI) 7-17%; normal <1.0%) correlated significantly (p<0.0001) w ith daily (median ranged from 39 to 47 mg; normal <3 mg; r=0.76-0.82) and f our day faecal calprotectin excretion (median 101 mg; 95% CI 45-168 mg; nor mal <11 mg; r=0.80) and single stool calprotectin concentrations (median 11 8 mg/l; 95% CI 36-175 mg/l; normal <10 mg/l; r=0.70) in patients with Crohn 's disease. The cross sectional study showed a sensitivity of 96% for calpr otectin in discriminating between normal subjects (2 mg/l; 95% CI 2-3 mg/l) and those with Crohn's disease (91 mg/l; 95% CI 59-105 mg/l). With a cut o ff point of 30 mg/l faecal calprotectin has 100% sensitivity and 97% specif icity in discriminating between active Crohn's disease and irritable bowel syndrome. Conclusion-The calprotectin method may be a useful adjuvant for discriminat ing between patients with Crohn's disease and irritable bowel syndrome.