Utility of IBD Serology Tests: Experience at a Midwest Academic Center

Abstract

Purpose: The diagnosis of inflammatory bowel disease (IBD) is based on clinical, radiographic, endoscopic and histological criteria. Recently, serology tests involving antibodies against microbial and auto antigens are being increasingly used as well for the diagnosis and management of IBD. Serological testing for IBD is non-invasive and easily available. However, the clinical value of these tests is still being evaluated and debated. Therefore, we conducted a retrospective study in our Midwest academic center to evaluate the sensitivity and specificity of the IBD serological tests. Methods: A retrospective study at the University of Missouri - Columbia from March 20, 1998 to February 22, 2008 involving all patients who underwent serology testing consisting of Prometheus IBD First Step Confirmatory System or IBD Serology 7 was performed. Patients were identified by a search conducted through Prometheus Laboratories. Of those patients identified, an extensive chart review was performed. Results of serology studies and final diagnoses (based upon all clinical criteria) were identified and recorded for each patient. Statistical analysis was performed in which the sensitivity and the specificity were calculated. Results: The search identified 173 patients between the ages of 18 to 82 years, comprising of 100 females and 73 males. Of these patients, 94 had the IBD First Step Confirmatory system and 79 had the IBD Serology 7 performed. A total of 77 patients had positive results on IBD serology (30 IBD First Step and 47 IBD Serology 7). A total of 96 patients had negative results on IBD serology (64 IBD First Step and 32 IBD Serology 7). A total of 82 patients were found to have IBD (42 IBD First Step and 40 IBD Serology 7) based upon clinical criteria consisting of clinical, radiographic, endoscopic, and histological evidence. The sensitivity and specificity of the IBD First Step Confirmatory System was 54.7% and 86.5%, respectively. The sensitivity and specificity of the IBD serology 7 was 80% and 61.5%, respectively. Conclusion: The sensitivity and specificity of the IBD serology tests performed in our Midwest tertiary-care center was much lower than previously reported. Several factors may have contributed to this discrepancy with the most notable being population differences. Further studies into these factors may be helpful to further elucidate the role of IBD serology testing.