Accuracy of Rapid Fecal Calprotectin Test in Monitoring Inflammatory Bowel Diseases Under Treatment with TNFα Antagonists

Background Anti-TNF alpha antibodies are effective in treating inflammatory bowel diseases (IBDs) unresponsive to the standard treatments. Information about the role of rapid fecal calprotectin (FC) in monitoring ambulatory IBD patients under treatment with anti-TNF alpha is lacking. Our aim was to assess the accuracy of rapid FC in monitoring those patients. Methods Seventy-two patients (38 males, 34 females, mean age 42.5 years, range 23-57 years), affected by ulcerative colitis (UC) (20 patients) or by Crohn's disease (CD) (52 patients) were treated with anti-TNFa antibodies. FC was assessed by a rapid semiquantitative test. Results With respect to the absence of clinical remission, FC test showed sensitivity of 71.8 %, specificity of 65.2 %, PPV of 41.8 %, and NPV of 86.9 %. In UC patients, FC test showed a sensitivity of 66.7 %, a specificity of 56.1 %, a PPV of 18.2 %, and a NPV of 92.0 %. In CD patients, FC test showed sensitivity of 70.6 %, specificity of 65.2 %, PPV of 50.0 %, and NPV of 81.8 %. With respect to the presence of endoscopic lesions, FC test showed sensitivity of 73.5 %, specificity of 96.0 %, PPV of 96.2 %, and NPV of 72.7 %. In UC patients, FC test showed sensitivity of 47.2 %, specificity of 84.6 %, PPV of 89.5 %, and NPV of 36.7 %. In CD patients, FC test showed sensitivity of 90.1 %, specificity of 79.7 %, PPV of 71.9 %, and NPV of 93.3 %. Conclusions Diagnostic accuracy of rapid FC seems better in predicting persistence of endoscopic lesions than clinical remission in IBD patients under treatment with anti-TNF alpha.