Variability of Faecal Calprotectin in Inflammatory Bowel Disease patients: an Observational Case-Control Study.
J Crohns Colitis. 2019 Apr 04;:
Authors: Cremer A, Ku J, Amininejad L, Bouvry MR, Brohet F, Liefferinckx C, Devière J, van Gossum A, Smet J, Stordeur P, Franchimont D
BACKGROUND AND AIMS: Several factors have been reported to affect faecal calprotectin (FC) values, and signiﬁcant variation in FC concentrations has been observed in inflammatory bowel disease (IBD) patients. We aimed to evaluate FC variability in IBD patients, and to assess the robustness of a single stool punch.
METHODS: This is a single center observational case-control study. Disease activity was assessed using endoscopic and clinical activity scores, as well as C-reactive protein levels. Stool samples were collected twice within 1 to 6 days interval and FC was measured on punches and homogenates by fluorometric enzyme immunocapture assay.
RESULTS: 260 stool samples were collected from 120 patients. Intra-stool variability was low with an intraclass correlation coefficient for single measures between 3 punches from a single stool sample of 0.91, and median coefficient of variation (CV) of 17%. CV of two stool samples a few days apart (intra-individual variability) were significantly higher (p<0.01) with median CV of 36%. FC standard deviations correlated with mean FC levels either for intra-stool or for intra-individual variability with a Spearman’s coefficient of rank correlation of 0.85 and 0.78 respectively (p<0.01). Disease type, location, activity, and FC levels do not influence variability.
CONCLUSION: A single stool punch is reliable for FC measurement, considering that intra-stool variability is low. Intra-individual variability a few days apart is significantly higher. Therefore, decision-making strategies based on single measurements should consider this variability to determine the minimum optimal variation to be achieved, rather than a cut-off, especially in high FC levels.
PMID: 30944925 [PubMed – as supplied by publisher]