Els van de Vijver

24 Box 1. Criteria used to define a population of children and teenagers with a clinical suspicion of IBD. Persisting diarrhoea (>4 weeks) OR recurrent (≥ 2 episodes in 6 months) abdominal pain and diarrhoea AND at least one of the following criteria: rectal blood loss unintended weight loss or linear growth retardation peri-anal symptoms (skin tag, fistula, fissure, abscess) Anaemia (Hb cut-off point in mmol/L): < 12 y: 7.1; girls ≥ 12 y: 7.4; boys ≥ 12 y: 8.1 [15] or other extra-intestinal manifestations (erythema nodosum, arthritis, uveitis) Increased markers of inflammation: ESR > 20 mm/hr; C-reactive protein > 10 mg/L Data collection After the first presentation at the outpatient clinic, all patients provided a stool sample collected at home. The faecal samples were analysed at the Department of Laboratory Medicine in the UMCG by a commercially available quantitative assay (CALPRO®ELISA test (ALP), Calpro AS, Lysaker, Norway). The manufacturer cut-off point is 50 µg/g stool. Laboratory technicians were blinded to the final diagnosis of the patients. The decision to perform any other diagnostic tests (including endoscopy) was left to the paediatric gastroenterologist’s discretion and was independent of the faecal calprotectin result. Confirmation of IBD was obtained after endoscopic and histological evaluation according to the ESPGHAN Porto Criteria.(4) The diagnosis “non-IBD” was made when other test results gave a convincing explanation for the symptoms, or when the symptoms had completely resolved at 6-month follow-up. An experienced paediatric histopathologist, who was blinded to the results of other diagnostic tests, assessed each biopsy specimen. Stool cultures were evaluated for Salmonella, Shigella, Yersinia, Campylobacter, Clostridium difficile (inclusive of toxin A and B), Giardia Lamblia, Entamoeba histolytica an parasites. ( Fig 1 ) Chapter 2