Arch Dis Child. 2020 Oct;105(10):957-963.doi: 10.1136/archdischild-2019-317823. Epub 2020 May 18.

Gareth J Walker ^1 2, Neil Chanchlani ^2 3, Amanda Thomas ^1 2, Simeng Lin ^1 2, Lucy Moore ⁴, Neel M Heerasing ^1 2, Peter Hendy ^1 2, Mohamed Abdelrahim ¹, Sean Mole ¹, Mandy H Perry ⁵, Timothy J Mcdonald ^4 5, Claire M Bewshea ², James W Hart ³, Richard K Russell ⁶, Tariq Ahmad ^1 2, James R Goodhand ^1 2, Nicholas A Kennedy ^7 2

• ¹Gastroenterology, Royal Devon and Exeter Hospital, Exeter, UK.
• ²Exeter IBD Pharmacogenetics, University of Exeter Medical School, Exeter, UK.
• ³Paediatrics, Royal Devon and Exeter Hospital, Exeter, UK.
• ⁴The College of Medicine & Health, University of Exeter, Exeter, UK.
• ⁵Biochemistry, Royal Devon and Exeter Hospital, Exeter, UK.
• ⁶Paediatric Gastroenterology, The Hospital For Sick Children, Edinburgh, UK.
• ⁷Gastroenterology, Royal Devon and Exeter Hospital, Exeter, UK nick.kennedy1@nhs.net.

Author information

Abstract

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.