Objective To determine the diagnostic accuracy of calprotectin to diagnose inflammatory bowel disease (IBD) in children in whom general practitioners (GPs) suspected IBD.
Design Prospective observational cohort study of a new calprotectin-based primary care referral pathway.
Setting 48 GP practices and gastroenterology secondary care services at the Royal Devon and Exeter NHS Foundation Trust in the South-West of England, UK.
Patients 195 children aged between 4 and 18 years referred on the pathway between January 2014 and August 2017 for investigation of gastrointestinal symptoms were included.
Interventions Primary-care-driven faecal calprotectin testing. Primary and secondary care records over 12 months from the point of calprotectin testing were used as the reference standard.
Main outcome measures Diagnostic accuracy of calprotectin testing to detect IBD.
Results 7% (13/195) tested patients were diagnosed with IBD. Using our prespecified cut-off of 100 µg/g, calprotectin had a diagnostic accuracy of 91% (95% CI 86% to 95%) with a sensitivity for distinguishing IBD from non-IBD of 100% (95% CI 75% to 100%), a specificity of 91% (95% CI 85% to 94%), a positive predictive value of 43% (95% CI 25% to 63%) and a negative predictive value of 100% (95% CI 98% to 100%). Calprotectin testing had no effect on the time to diagnosis, but a negative test contributed to saved referrals and was associated with fewer diagnostic tests in secondary care.
Conclusions Calprotectin testing of children with suspected IBD in primary care accurately distinguishes IBD from a functional gut disorder, reduces secondary care referrals and associated diagnostic healthcare utilisation.
- primary care
- diagnostic tests
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Contributors GW, JH, RKR, TA, JRG and NAK participated in the conception and design of the work. CB was the project manager and coordinated recruitment. MHP and TJM coordinated all biochemical analysis and central laboratory aspects of the project. GJW, NC, AT, SL, LM, NMH, PH, MA, SM, JWH, RKR, TA, JRG and NAK were involved in the acquisition, analysis or interpretation of data. The data analysis was performed by GW and NAK. Drafting of the manuscript was conducted by GW, NC, AT, SL, JWH, RKR, TA, JRG and NAK. All the authors contributed to the critical review and final approval of the manuscript. TA obtained the funding for the study.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests GJW has consulted for AbbVie and received honoraria from Falk and AbbVie for unrelated topics and a fellowship from NIHR. NC is funded by a PhD studentship by Crohn’s and Colitis UK. RKR reports honoraria from Abbvie, Ferring, Therakos and Celltrion, grants from Nestec, outside the submitted work. TA has received unrestricted research grants, advisory board fees, speaker honorariums and support to attend international meetings from AbbVie, Merck, Janssen, Takeda, Ferring, Tillotts, Ferring, Pfizer, NAPP, Celltrion, Hospira for unrelated topics. JRG received honoraria from Falk, Abbvie and Shield therapeutics for unrelated topics. NAK has consulted for Falk and received honoraria from Falk, Allergan, Pharmacosmos and Takeda for unrelated topics and is a deputy editor of Alimentary Pharmacology & Therapeutics Journal; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request.
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