Introduction Faecal calprotectin (FC) is a calcium binding protein found mainly in the neutrophil cytosol. It is a non-invasive marker to differentiate between IBS and IBD and can avoid need for specialist referral or further investigations. Current cut off for the FC normal limit in initiating further investigations is 50–59 μg/g. Studies have shown low diagnostic yield of colonoscopy in patients with borderline FC (50–100 μg /g). If the current FC cut off is raised, this would prevent subjecting patients to unnecessary colonoscopies and also reduce the financial burden on the health services. The aim of the study was to determine diagnostic yield of investigations in patients presenting with new lower GIT symptoms and mildly elevated FC 100–200 μg /g to assess if it is justifiable to expose patients to colonoscopy at levels less than 200 μg /g.

Methods Retrospective study was conducted on 251 patients with FC more than 60μg/g from October 2014 to December 2014 in West Yorkshire. Data was collected from the biochemistry department’s database in Midyorks Hospital and analysed.

Results 251 patients were identified with FC > 60 μg /g. Out of these, 109 patients had further investigations. 142 were not investigated due to miscellaneous reasons. Out of 109, 37 patients (33.9%) had FC between 60–100 μg /g, 27 patients (24.8%) had FC between 101–200 μg /g, 17 patients (15.6%) had FC between 201–300 μg /g and 28 (25.7%) had it between 301–1700 μg /g. In patients with FC 60–100 μg /g, only two patients (5%) had mild localised inflammation not requiring treatment. In 27 patients with FC between 101–200 μg /g, only two had findings on colonoscopy. One had rectal tumour and had initially presented with PR bleed. The other one had mild inflammation not requiring treatment.

In our study, in the group of patients between FC 200–300 μg /g, only 2/17 had findings (1 had proctitis and the other had focal active inflammation). However, in patients with FC > 300, 13 /28 (46%) were found to have abnormalities on colonoscopy (4 with colitis, 3 with ileitis, 3 had proctitis, 1 SRUS, 1 collagenous colitis and 1 focal active inflammation).

Conclusion In patients with FC < 200 μg /g, there was no diagnostic yield of invasive investigations like colonoscopy in the absence of any warning signs. In patients with FC 200–300 μg /g, diagnostic yield increased slightly. We recommend all patients with FC > 300 μg /g and new GIT symptoms to be referred for colonoscopy. Any figures less than that should be individually assessed for warning signs before investigating further with colonoscopy.

Reference 1 Seenan JP, Thomson F, Smith K, Gaya DR. “Are we exposing patients with a mildly elevated faecal calprotectin to unnecessary investigations?” Frontline Gastroenterology 2015;6(3):156–160

Disclosure of Interest None Declared