Diagnostic Accuracy of Fecal Calprotectin for Pediatric Inflammatory Bowel Disease in Primary Care: A Prospective Cohort Study

Abstract

PURPOSE In specialist care, fecal calprotectin (FCal) is a commonly used noninvasive diagnostic test for ruling out inflammatory bowel disease (IBD) in children with chronic gastrointestinal symptoms. The aim of this study was to evaluate the diagnostic accuracy of FCal for IBD in symptomatic children in primary care. METHODSWe studied 2 prospective cohorts of children with chronic diarrhea, recurrent abdominal pain, or both: children initially seen in primary care (primary care cohort) and children referred to specialist care (referred cohort). FCal (index test) was measured at baseline and compared with 1 of the 2 reference standards for IBD: endoscopic assessment or 1-year follow-up. Physicians were blinded to FCal results, and values greater than 50 μg/g feces were considered positive. We determined specificity in the primary care cohort and sensitivity in the referred cohort. RESULTSNone of the 114 children in the primary care cohort ultimately received a diagnosis of IBD. The specificity of FCal in the primary care cohort was 0.87 (95% CI, 0.80-0.92). Among the 90 children in the referred cohort, 17 (19%) ultimately received a diagnosis of IBD. The sensitivity of FCal in the referred cohort was 0.99 (95% CI, 0.81-1.00).CONCLUSIONS The findings of this study suggest that a positive FCal result in children with chronic gastrointestinal symptoms seen in primary care is not likely to be indicative of IBD. A negative FCal result is likely to be a true negative, which safely rules out IBD in children in whom a primary care physician considers referral to specialist care. 2016;14:437-445. doi: 10.1370/afm.1949. Ann Fam Med INTRODUCTIONP rimary care physicians frequently manage recurrent abdominal pain or diarrhea in children. These symptoms account for approximately 2% to 5% of all childhood consultations.1-3 Although they are typically functional in origin, it is essential that organic disease be ruled out. Inflammatory bowel disease (IBD), that is, Crohn disease and ulcerative colitis, is an organic disease that primary care physicians should not miss. Delay in diagnosing IBD, and the resultant delay in receipt of appropriate treatment, may prolong suffering and can lead to complications such as anemia, irreversible growth failure, and delayed sexual maturation. 4,5 According to guidelines, primary care physicians should refer children with chronic diarrhea, recurrent abdominal pain, or both for specialist care if red flags are present. 6,7 The red flags are nonspecific and discriminate poorly between functional and organic gastrointestinal diseases, [8][9][10] often leading to referral and extensive diagnostic testing. For children with functional disorders, referral or extensive testing may delay appropriate interventions and further decrease well-being. 11,12 Calprotectin is a calcium-binding protein released from neutrophils during intestinal inflammation that can be easily measured in feces. 13,14 In specialist care, evidence shows it to be a useful, simple, noninvasive test 438that can rule out ...

Use of Laboratory Markers in Addition to Symptoms for Diagnosis of Inflammatory Bowel Disease in Children

“…In only 1 study, 24 of 90 patients were initially assessed in primary care and referred to specialist care for further diagnostic workup. 10 More studies in primary care are needed to determine the added value of markers in this setting.…”

“…19 In our IPD meta-analysis, we included 2 additional studies, 10,29 1 of which was published after the earlier IPD. 10…”

Clinical usefulness of the faecal calprotectin test in suspected paediatric inflammatory bowel disease

“…A child with a low pre‐test probability of IBD is likely to still have a low post‐test probability of IBD if even he or she tests positive so the decision to subject a child with suspected IBD to endoscopies should be based on the clinical history and physical examination rather than on a positive FC test result. As it was shown in a recent study, a positive FC result in children with chronic gastrointestinal symptoms seen in primary care (where prevalence of IBD was low) was not likely to be indicative of IBD .…”

In This Issue: Different Paths to Discovery

“…Ways of discovery in this issue include: experimentation 1,2 and systematic synthesis of experimental evidence 3 ; simulations of process and outcomes of policy interventions 4 ; comparison of complementary perspectives 5,6 ; careful longitudinal observation [7][8][9] ; reflective witnessing [10][11][12] ; and readers' shared experiences and reflections 15 Two clinical trials provide experimental evidence against treatments that had shown promise in prior observational studies and small clinical trials. Smith et al test the hypothesis that asthmatic people who attempt to take probiotics daily might reduce respiratory infections, asthma exacerbations, or antibiotic use.…”

“…With a high negative predictive value, a negative fecal calprotectin appears to be useful in ruling out inflammatory bowel disease in children with chronic gastrointestinal symptoms. 8 Brooks uses a different kind of longitudinal observation-oral histories of 52 primary care physicians-and discovers 5 decades of discouragement and disparagement about primary care. This results in ongoing hostility toward primary care through the culture and structure of medical training.…”