Els van de Vijver

23 INTRODUCTION For the paediatrician treating a child with recurrent abdominal pain and diarrhoea it is often difficult to clinically distinguish between those who need an endoscopy and those who do not. Identification of children with low likelihood of organic disease would justify a non- invasive “watchful waiting” strategy, while a high likelihood of inflammatory bowel disease (IBD) would justify referral to specialist services for endoscopy. In a recently published diagnostic meta-analysis(1) we found that increased levels of calprotectin in the stool can identify children who are most likely to have IBD. All included studies used the fully paired design in which a group of patients first undergo faecal calprotectin testing and then endoscopy. These studies estimated the diagnostic accuracy of faecal calprotectin under ideal experimental circumstances. We conducted a phase III diagnostic accuracy study to determine whether faecal calprotectin could serve as a screening test to identify children with a high likelihood for IBD and reduce the number of children and teenagers undergoing invasive endoscopy. We aimed to determine an objective diagnostic strategy to minimise the number of children and adolescents with negative endoscopy results without missing any case of IBD. PATIENTS AND METHODS Study setting and participants This study was performed at the paediatric outpatient clinic of six general hospitals and one tertiary care hospital (University Medical Center Groningen (UMCG)) in the northern region of the Netherlands. Most paediatricians in the general hospitals were trained as fellows in paediatric gastroenterology and half of them had their training in the UMCG. Children and teenagers between 6 and 18 years of age with abdominal complaints were eligible for participation. Younger children have higher normal values of faecal calprotectin and were excluded for this reason.(2,3) Patients were included when they fulfilled the clinical case definition for suspected IBD. ( box 1 ) Ruling out IBD without referral for endoscopy