Diagnostic value of serological assays in pediatric inflammatory bowel disorders

Pediatric studies reported that the combined use of the anti-neutrophil cytoplasm autoantibodies (ANCA) and the anti-Saccharomyces cerevisiae mannan antibodies (ASCA) may be a specific useful noninvasive test in the diagnosis of inflammatory bowel diseases (IBD).

To evaluate the diagnostic accuracy of ANCA and ASCA in children with suspected IBD, and to see whether different commercially available assays (indirect immunofluorescence vs. ELISA) agree well enough in terms of analytical performance.

Sixty-nine children (30 males, 39 females, age range 2-18 years) with suspicion of IBD entered the study. Before colonoscopy, a blood sample was also drawn to assess ASCA and ANCA.

A diagnosis of IBD was established in 47 patients; the remainder had infective or other causes of colitis. For ulcerative colitis, the association ASCA-/ANCA+ had 70% sensitivity and 86% specificity, with a positive predictive value of 82%. The association ASCA+/ANCA- had 86% sensitivity and 93% specificity for Crohn's disease, with a positive predictive value of 75%.

Although more experience is needed to state the diagnostic power of serologic assay, determination of ANCA and ASCA in IBD children may help both in distinguish these conditions from other entities and ulcerative colitis from Crohn's disease, particularly in doubtful cases.