Prediction of endoscopic disease activity in XXXX by two different assays for faecal calprotectin.

@entity1 @entity32 @entity33 @entity31 @entity29
UNASSIGNED: Background and aims As @entity33 is the goal of treatment in @entity29 , defining a faecal (f-) calprotectin cut-off level for @entity33 is crucial. Previous studies have presented different cut-off levels. The aim of this study was to investigate the ability of two f-calprotectin assays to differentiate @entity33 from @entity32 in @entity31 . Methods Sixty-two @entity1 with @entity31 underwent colonoscopy for classification of @entity32 (Mayo endoscopic subscore). The @entity1 also submitted a faecal sample for f-calprotectin analysis using two different ELISA assays, Calpro ELISA and B  hlmann ELISA. Results The two assays correlated significantly, with a Spearman rank correlation coefficient of 0.86. Both assays showed significantly different f-calprotectin levels in @entity1 with a Mayo endoscopic subscore of 0 ( @entity33 ) and 1-3 (inflamed mucosa) (p < 0.001). Using ROC curve analyses we selected the best cut-off levels for both assays with responding sensitivity and specificity (presented with 95% confidence intervals); Calpro ELISA cut-off 61  g/g, sensitivity 84.1 % (75.0-93.2%), specificity 83.3 % (74.0-92.6%), and B  hlmann ELISA cut-off 96  g/g, sensitivity 90.9 % (83.7-98.1%), specificity 83.3 % (74.0-92.6%). Defining @entity33 as a Mayo endoscopic subscore  <= 1, cut-off levels increased; Calpro ELISA cut-off 110  g/g, sensitivity 80.0 % (70-90%), specificity 66.6 % (54.9-78.3%), and B  hlmann ELISA cut-off 259   g/g, sensitivity 83.3 % (74-92.6%), specificity 71.9 % (60.7-83.1%). Conclusions The study demonstrates the need for assay specific cut-off levels in clinical practice, as the f-calprotectin cut-off level for endoscopic disease activity differed in these two assays.
