Comparison of six different calprotectin assays for the assessment of inflammatory bowel disease

BACKGROUND AND OBJECTIVES

Faecal calprotectin is a valuable noninvasive marker for inflammatory bowel disease (IBD). The aim of our study was to determine the correlation between six different calprotectin assays and compare their performance for diagnosis and follow up of IBD.

METHODS

Thirty-one patients with suspected IBD and 31 patients in follow up were included. We determined calprotectin by means of three rapid immmunochromatographic tests, two enzyme-linked immunosorbent assays, and one automated fluoroimmunoassay. Results were correlated with endoscopic and histological findings.

RESULTS

Although all methods correlated significantly, slopes and intercepts differed extensively, with up to 5-fold quantitative differences between assays. Sensitivity and specificity for diagnosis of IBD were 82-83 and 84-89%, respectively. For follow up, sensitivity in detecting mild ulcerative colitis was 71-100%. In moderate-to-severe ulcerative colitis, sensitivity was 100% for all assays. Specificity was 67-86% in both subgroups. In Crohn's disease, only moderate-to-severe disease could be differentiated from remission, with sensitivity 83-86% and specificity 75% for all tests.

CONCLUSIONS

All calprotectin assays showed comparable clinical performance for diagnosis of IBD. For follow up, performance was acceptable, except for mild Crohn's disease. Because of the large quantitative differences, further efforts are needed to standardize calprotectin assays.

Cytomegalovirus colitis in an apparently immunecompetent host after biliopancreatic diversion for obesity

CMV colitis in an immunocompetent host is a rare occurrence. We report a case of CMV colitis after biliopancreatic diversion surgery. The diagnosis of primary CMV infection with CMV colitis was based on histological examination of tissues biopsies obtained at colonoscopy, serology positive for CMV-IgM and CMV-IgG antibodies and a good response to systemic gancyclovir treatment. Malnutrition and colonic mucosal damage, both consequences of biliopancreatic diversion surgery, were thought to be predisposing factors. To our knowledge this is the first report in the English language literature of an association between CMV colitis and status following biliopancreatic diversion surgery.