Fecal ASCA Measurements in the Assessment of Pediatric Patients with Known or Suspected Crohnʼs Disease

Abstract

Purpose: To examine the utility of measuring fecal ASCA levels as a non-invasive screening measure for CD in children with known or suspected IBD. Methods: 105 patients aged ≤ 18 years, including 86 patients with CD, 17 with UC, 2 with acute colitis, and 16 healthy controls submitted stool and serum specimens for ASCA analysis. Diagnosis of IBD was based on endoscopic, radiologic, and histologic findings. Fecal samples were diluted 1:10 and analyzed using a qualitative ASCA ELISA immunoassay. Fecal ASCA samples were measured blinded of a subject's diagnosis. Results: 52% (45/86) of patients with CD and 30% (5/17) patients with UC tested positive for fecal ASCA. None of the healthy controls tested positive for fecal ASCA. The sensitivity and specificity for fecal ASCA testing was 52% and 62%, respectively. Serum ASCA results were available from 71 subjects. The sensitivity and specificity of serum ASCA measurements in these subjects was 86% and 55%, respectively. Conclusions: The prevalence of antibodies to ASCA appears to be comparable in stool or serum. The specificity of serum ASCA testing is superior to that measured in the feces. However, fecal ASCA testing offers the advantage of being inexpensive and noninvasive. When combined with other fecal diagnostic assays, such as lactoferrin, fecal ASCA testing may prove useful for the assessment of children suspected of having IBD.