Els van de Vijver

46 Baseline characteristics are presented in Table 1 . The patients in the high risk stratum were older, had more red flag symptoms and higher calprotectin concentrations than those in the low risk stratum. Three patients who were initially in the low risk stratum were later found to have IBD. All three had elevated faecal calprotectin concentrations (range 340 to 480 µg/g) and a positive PCR result. Table 1: Baseline characteristics of patients with chronic abdominal pain and diarrhoea stratified into high and and low risk for inflammatory bowel disease (IBD). Values are number (%) unless otherwise stated. Characteristics High risk (n=142) Low risk (n=195) Reference test Endoscopy Clinical follow-up Demographics Median age in years (interquartile range) 14 (11-15) 12 (9-14) Male gender 67 (47%) 112 (57%) Major red flag symptoms Overt rectal blood loss 90 (63%) 0 (0%) Perianal disease (superficial anal fissures excluded) 20 (14%) 0 (0%) Minor red flag symptoms Weight loss or linear growth deceleration 52 (37%) 47 (24%) Extra-intestinal symptoms (including arthritis) 20 (14%) 13 (7%) Family history of IBD 12 (9%) 18 (9%) Anaemia (haemoglobin <-2 SD for age and gender) 56 (39%) 19 (10%) Increased markers of inflammation (C-reactive protein> 10 mg/L or erythrocyte sedimentation rate >20 mm/hr) 58 (41%) 10 (5%) Stool test Increased calprotectin (>50 µg/g) 125 (88%) 76 (39%) Ongoing or worsening symptoms despite eradication of the pathogen made the clinician decide to proceed to endoscopy. The distributions of calprotectin and calgranulin-C values per final diagnosis are shown in Figure 3 . Chapter 3