Clinical utility of serodiagnostic testing in suspected pediatric inflammatory bowel disease

OBJECTIVES: Confronted with nonspecific symptoms, accurate screening tests would be useful to clinicians to distinguish between functional childhood d isorders and inflammatory bowel disease (IBD), thus avoiding invasive diagn ostic testing. Traditional ulcerative colitis-specific perinuclear antineut rophil cytoplasmic antibody (pANCA) and Crohn's disease-specific anti-Sacch aromyces cerevisiae antibody (ASCA) serodiagnostic assays have recently bee n modified, with ELISA cut-off values recalculated to maximize sensitivity. The aim of this study was to determine whether the combination of these se rodiagnostic tests could maximize diagnostic accuracy and minimize invasive investigations in pediatric patients presenting with nonspecific symptoms suggestive nf IBD. METHODS: With investigators blinded to clinical diagnoses, ASCA, ANCA, and pANCA profiles were obtained prospectively from 128 patients undergoing com plete diagnostic evaluation for IBD. In phase I, diagnostic accuracy and pr edictive values of the modified and traditional assays were compared for th e IBD (n = 54) and non-IBD groups (n = 74). In phase II, the overall accura cy of a novel sequential diagnostic testing strategy was determined. Additi onally, the potential number of invasive investigations avoided with the hy pothetical application of this strategy to the cohort was determined. RESULTS: For phase I, the modified serodiagnostic assay was more sensitive (81 vs 69%), whereas the traditional assay had a higher specificity (96 vs 72%) for IBD (p < 0.05) For phase II, false-positive diagnoses would have b een reduced by 81%, yielding an overall sequential testing strategy accurac y of 84%. CONCLUSIONS: The incorporation of sequential noninvasive testing into a dia gnostic strategy may avoid unnecessary and costly evaluations and facilitat e clinical decision making when the diagnosis of IBD in children is initial ly uncertain. <(c)> 2001 by Am. Cell. of Gastroenterology.