P174 Optimal time interval required for correlation between fecal calprotectin test and endoscopy
Jeon S.R., Kim H.G., Kim J.-O., Jung Y., Ko B.M., Lee M.S.
Soonchunhyang University College of Medicine, Seoul, South Korea
Fecal calprotectin (FC) concentration has been reported to show good correlation with the degree of inflammation observed in endoscopy, in both Crohn's colitis (CD) and ulcerative colitis (UC). For more precise correlation between FC and endoscopic inflammation, patients need to provide a stool sample at the same time of endoscopy. However, in real practice, two tests can be hardly performed at the same time. Therefore, we aimed to investigate the time interval between FC test and endoscopy to have a good correlation in assessment of IBD activity.
Fifty eight patients with IBD (ileocolonic or colonic CD, n=10; UC, n=48) who had undergone endoscopy and FC test were retrospectively analyzed. FC test performed within 3 months were included in evaluation. FC level >200 ug/g was defined relapse of quiescent IBD. Degree of inflammation was assessed using endoscopy-based classification of inflammation for CD and Mayo endoscopic subscore for UC. After assessing concordance between FC and endoscopic score, correlation to the time interval was assessed by receiver operator curves (ROCs).
Median FC levels were 1050 (range 93–6000) ug/g in CD and 305 ug/g (range 6–6893) in UC. Mean time interval between FC test and endoscopy was 18.1±24.4 days. Endoscopic score and FC level were well correlated (r=0.694, p=0.026) in CD patients. In UC, Mayo endoscopic subscore showed a weak positive correlation to FC level (r=0.381, p=0.008). ROC analysis suggested that the best cut-off of the time interval for separation of non-correlation and correlation between endoscopic activity and FC level was 48 hours with a sensitivity of 68.4% and a specificity of 51% (AUC, 0.616; 95% CI 0.464–0.768).
FC level within 48 hours could reflect endoscopic activity in patients with IBD. In case of endoscopic examination for treatment decision in IBD patients with high level FC, 48 hours of time interval is recommended.