A recent article suggests that fecal calprotectin, while good, is not as good as endoscopy at detecting mucosal disease in pediatric Crohn’s disease (Inflamm Bowel Dis 2012; 18: 1493-97).

In this study, 60 consecutive children with new onset untreated Crohn’s disease (diagnosis based on Porto criteria -JPGN 2005; 41: 1-7) were enrolled in ESPGHAN growth study.  The data for this study was collected prospectively (21 investigators from multiple sites).  The calprotectin values were obtained prior to treatment.

Median fecal calprotectin values were 2198 μg/g in patients with isolated small bowel disease; this did not differ significantly from the value of 2400 μg/g in patients with colonic disease (with or without small bowel disease).

Fecal calprotectin was elevated in 95% of patients; this outperformed CRP (86%) and ESR (83%) as a marker for Crohn’s disease.  In the three children with normal calprotectin values, the serum inflammatory markers were normal in all three and two had minimal endoscopic findings.  The histology findings for these three children were not reported.

In my experience, fecal calprotectin has been very useful as a marker for Crohn’s disease and has helped identify some atypical cases by increasing my clinical suspicion.  I have had two patients with high calprotectin values who had normal-appearing mucosa with panendoscopy; they both had small bowel (jejunal) Crohn’s disease; one of these patients did have granulomas identified histologically.

While I realize that no test is perfect, I think additional studies are warranted to determine the actual sensitivity of this test for Crohn’s disease.  The sensitivity of calprotectin may yet be higher than the 95% reported in this study.

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