P205. A new rapid test for fecal calprotectin (FC) predicts mucosal healing in ulcerative colitis (UC)
T. Lobaton Ortega1, F. Rodriguez-Moranta1, J. Guardiola1, A. Lopez-Garcia1, E. Sanchez-Pastor1, L. Rodriguez Alonso1, S. Maistrerra1
1Hospital Universitari Bellvitage, Gastroenterology, Barcelona, Spain
Background: Several studies have assessed the correlation between fecal calprotectin (FC) and endoscopic activity in UC, but only few have tried to establish thresholds for the prediction of mucosal healing (MH). In addition, measurement of FC by Enzyme-linked immunosorbent assay (ELISA) limits its use because of the delay in obtaining the test results and subsequent delay in decision-making. Data on rapid tests (a quantitative test based on inmunocromatography which gives results in 12 minutes) on predicting MH is scarce.
Aims and Methods: Aims: To evaluate the capacity of FC to discriminate between the different levels of endoscopic activity. To establish a cut-off level of FC in order to predict MH. To demonstrate the correlation between ELISA and rapid tests.
Setting: Inflammatory Bowel Disease Unit from a referral hospital from Barcelona (Hospital de Bellvitge).
Design: transversal and prospective.
Patients: 88 CU patients referred for colonoscopy between December 2010 and July 2011.
Variables: Mayo Clinic Score, serological biomarkers (CRP, ESR, leukocytes and platelets), Mayo Endoscopic subscore, FC determined by Bühlmann ELISA® and Bühlmann QUANTUM BLUE® (rapid test).
Results: The rapid test showed a good correlation with ELISA (r = 0.83).
Mayo endoscopic subscore correlated closest with FC (Pearson rank correlation coefficient r = 0.76, p < 0.001) followed by clinical activity (r = 0.71, p < 0.001), CRP (r = 0.355, p < 0.001), ESR (r = 0.338 p < 0.004), platelets (r = 0.362, p < 0.001) and leucocytes (r = 0.259, p < 0.18).
FC was able to discriminate between the different levels of endoscopic activity according to Mayo score (median levels of FC ± SD): Mayo 0/1 (89.4±122.6/441.2±647.4; p < 0.001); Mayo 1/2 (441.2±647.4/2004.1±1142.0, p < 0.001); Mayo 2/3 (2004.1±1142.0/2436.1±1116.4, p = 0.450).
In the multivariate analysis, both FC and clinical activity were independent predictive variables of endoscopic activity. However, the accuracy to predict MH, defined by area under the curve (AUC), was better for FC (AUC = 0.94) than for Mayo clinic score (AUC = 0.87) and even better with a combination of both of them. A cutoff level of 250 ug/g had a sensivity of 94% and specificity of 80%.
Conclusions: FC correlated closest to endoscopic activity than the rest of the markers and was able to discriminate between the different levels of activity.
The good correlation between rapid tests and ELISA enables us to use rapid tests in order to take fast and adequated decisions.