Clinical indications of the use of antineutrophil cytoplasmic antibodies and anti-Saccharomyces cerevisiae antibodies in the evaluation of inflammatory bowel disease at an Academic Medical Center

Abstract

Background: Serological markers for inflammatory bowel disease (IBD), including anti-neutrophil cytoplasmic antibody (ANCA) and anti-Saccharomyces cerevisiae antibody (ASCA), have a high specificity and positive predictive value in diagnosing IBD. However, neither indication nor use in clinical practice has been clearly established. This study aimed to determine the clinical impact of ANCA/ASCA testing by evaluating how these tests were used in an academic referral center. Methods: Retrospective chart review to classify the indications for testing and effect on diagnosis or management. Results: Seventy-six patients had serological tests for IBD. Indications included differentiating ulcerative colitis (UC) from Crohn's disease (CD) in established patients with IBD (13%); establishing a diagnosis in patients with atypical signs of inflammation as detected by endoscopy, histology, or radiology (50%); evaluation of chronic diarrhea (22%); evaluation of a family history of IBD (4%); and differentiating pouchitis from CD (4%). Review of the subsequent course indicated that serologic testing had an important role in diagnosis in 28% of patients, a supportive role in 26%, and was not helpful in 46%. Serologic testing clarified the clinical presentation in 61% of those presenting with atypical inflammatory changes. It proved valuable in establishing a diagnosis of UC or CD in a subset of middle-aged patients with inflammatory changes in the sigmoid colon. For patients with chronic diarrhea, the yield was lower: 36% had a significant effect on diagnosis, but test results changed immediate treatment in only 1 (6%). In patients being considered for operative management (n = 8), serologic testing was valuable in clarifying the diagnosis in 75% of patients and had an impact on the operative plan in 62% of patients. Conclusion: Serological testing for ANCA/ASCA may have a significant role in the diagnosis and treatment in individuals presenting with sigmoid inflammation or atypical inflammation but was less useful in those with chronic diarrhea. Copyright © 2005 by Lippincott Williams & Wilkins.