Assessing the presence and degree of intestinal inflammation objectively, simply and reliably, is a significant problem in gastroenterology.
The report in October’s issue of Gut assessed fecal excretion of calprotectin, a stable neutrophil-specific marker, as an index of intestinal inflammation.
Calprotectin is > 60% of cytosolic protein in neutrophils.
Calprotectin accounts for more than 60% of cytosolic protein in neutrophils. It resists degradation by intestinal bacteria, and is stable in stool for up to one week at room temperature.
The researchers investigated the potential use of this marker, as a screening test to discriminate between patients with Crohn's disease and those with irritable bowel syndrome.
The validity of fecal calprotectin as a marker of intestinal inflammation was assessed in 22 patients with Crohn's disease (35 studies) by comparing with fecal excretion of 111indium white cells. Four-day fecal excretion of 111indium correlated significantly (p < 0.0001) with daily and 4-day fecal calprotectin excretion, but more importantly with single stool calprotectin concentration.
A cross-sectional study assessed the use of fecal calprotectin concentration for the detection of established Crohn's disease (n = 116). Calprotectin had a sensitivity of 96% in discriminating between normal subjects (2 mg/L) and those with Crohn's disease (91 mg/L).
A prospective study assessed the value of fecal calprotectin in discriminating between patients with Crohn's disease and irritable bowel syndrome in 220 patients referred to a gastroenterology clinic. With a cut-off point of 30 mg/L, fecal calprotectin has 100% sensitivity and 97% specificity.
Dr J Tibble and colleagues conclude that the calprotectin method may be a useful adjuvant for discriminating between patients with Crohn's disease and irritable bowel syndrome.