Introduction Faecal calprotectin (fcal) is a non-invasive marker of intestinal inflammation that can assist physicians in investigating chronic gastrointestinal (GI) symptoms. Different cut-off values have been proposed, depending on the pre-test probability for organic disease, in order to improve diagnostic accuracy and to make the test more cost-effective. To support the use of a higher cut-off in clinical practice, we present data from a cohort of patients having been fully investigated for fcal levels above the lab reference cut-off.

Method Retrospective observational study.

Results We identified the patients who were referred to the Gastroenterology department at King’s College Hospital, London, UK between January 2002 and 2004 with chronic gastrointestinal symptoms and had a fcal test. During this period 367 patients were tested. Two hundred (200/367, 55%) were given a diagnosis of non-organic disease and were discharged to their primary care physician. Sixty one (61/200, 31%) with a median age of 48 years (range 21, 85) and 2:1 female: male ratio tested positive for fcal (>60 μg/g, ELISA kit, Bühlmann). Thirty five (35/61, 57%) had presented initially with altered bowel habit, 15 (25%) with abdominal pain, 7 (12%) with bloating and 4 (6%) with diarrhoea. The median fcal was 113 μg/g (range 60, 850, >150 μg/g in 18 [30%] patients). All had a normal ileocolonoscopy. The median follow up time from initial presentation to the initiation of this study was 10 years (range 9, 11). In this period 3 patients (3/61, 5%) were diagnosed with an organic condition. Two were diagnosed with Crohn’s disease (1 with terminal ileal [TI] and 1 with isolated perianal disease) after 7 years of their initial presentation and 1 with collagenous colitis after 5 years. The repeat fcal for the patient with TI disease increased from 80 μg/g to 1130 μg/g prior to diagnosis. The other two had normal fcal when retested. Four patients were found, in retrospect, to take NSAIDs regularly, three had a diagnosis of cystic fibrosis, two with liver cirrhosis and one had a diagnosis of HIV at the time of referral. None of the patients with a negative calprotectin developed organic disease during their follow-up.

Conclusion In patients presenting with chronic GI symptoms, fcal in the range 60–150 μg/g is associated with a very low incidence of organic or significant pathology. Subsequent routine investigation of these patients after normal colonoscopy (other than perhaps repeating fcal to demonstrate a trend over time) is not recommended.

Disclosure of interest None Declared.