Is NICE too optimistic about savings from normal faecal calprotectin results?

Abstract

Background: A recent systematic review confirmed the utility of faecal calprotectin (FC) in distinguishing organic (inflammatory bowel disease) from non-organic gastrointestinal disease (irritable bowel syndrome). FC levels <50 mcg/g have a negative predictive value >92% to exclude organic GI disease. Levels >250mcg/g correlate with endoscopic IBD disease activity; sensitivity 90%. This study aimed to determine clinical outcomes in those with a normal FC result.

Method: Adults (>16 years old) with FC results between July 2012 - October 2013 were reviewed. Clinical data was collected from hospital databases and General Practitioners (GPs). GPs were provided with a referral pathway prior introduction of FC in 2012.  Clinical data at 12 months post index FC test was available in 275 patients; 208 normal, 41 intermediate and 26 raised results.

Results: A new IBD diagnosis was made in only 1% of patients with a normal FC result. Conversely, a new IBS diagnosis was made in a further 40% of normal FC results referred to secondary care. Despite a normal FC and referral guidance, 40% of patients were still referred to secondary care.

Conclusions: Normal FC testing remains a useful test in excluding organic GI conditions, although 40% were still referred to secondary care despite a normal FC. Despite a normal FC, 6% still remained in secondary care at 12 months without a new diagnosis.