Background Up to 70% of children and teenagers referred to a paediatric gastroenterology centre with suspected inflammatory bowel disease (IBD) do not have the disease.

Objective To evaluate whether faecal calprotectin as an ‘add-on test’ improves the specificity of the clinical case definition for suspected IBD in a general paediatric practice.

Design A prospective diagnostic accuracy study.

Setting Six outpatient clinics for general paediatrics and one tertiary care hospital in the Netherlands.

Patients 117 children and teenagers with a clinical suspicion of IBD.

Diagnostic tests Faecal calprotectin was measured (index test) in all patients. Patients with a high index of suspicion on the basis of the paediatrician's global assessment, physical examination and blood results were referred for endoscopy (reference standard). Children and teenagers who were not selected for endoscopy initially were followed for half a year for the appearance of possible additional symptoms (delayed type reference standard).

Primary outcome The proportion of referred patients with confirmed IBD.

Results The mean age of patients was 14 years (range 6–18). A total of 42 (36%) had confirmed IBD. The paediatricians, who were blinded to the faecal calprotectin result, referred 68 children and teenagers for endoscopy. If they had referred only those patients with a positive faecal calprotectin result (>50 μg/g), 54 patients would have undergone endoscopy.

Limitation The study relied on clinical follow-up to detect missed IBD.

Conclusions A diagnostic strategy in general paediatric practice of using a simple clinical case definition for suspected IBD in combination with a positive faecal calprotectin result increases the specificity to detect IBD and reduces the need for referral to a paediatric gastroenterology centre with a very low risk of missing cases.