Perinuclear antineutrophil cytoplasmic autoantibodies and anti-Saccharomyces cerevisiae antibodies as serological markers are not specific in the identification of Crohn's disease and ulcerative colitis

OBJECTIVE: To evaluate the diagnostic accuracy of perinuclear antineutrophil cytoplasmic autoantibodies (pANCAs) and anti-Saccharomyces cerevisiae antibodies (ASCAs), as single agents and in combination, for the diagnosis of Crohn's disease (CD) and ulcerative colitis (UC),including in cases of indeterminate colitis (IC). METHODS: The sera from a total of 98 patients were studied: 77 with CD, 16 with UC and five with IC. The medical records of these patients were reviewed for disease diagnosis, demographic data, and patient symptoms and medications. ELISAs were utilized to detect the presence of ASCAs and deoxyribonuclease-sensitive pANCAs, and these results were then compared with the patients' clinical data. RESULTS: For UC, a positive pANCA test alone provided a sensitivity of 50% and a specificity of 82%. For CD, a positive ASCA test alone provided a sensitivity of 40% and a specificity of 100%. A combination of pANCA-positive and ASCA-negative results showed a sensitivity of 50% and specificity of 90% for the diagnosis of UC. Similarly, the combination of ASCA-positive and pANCA-negative results provided a sensitivity and specificity of 32% and 100% for the diagnosis of CD, respectively. Interestingly, 80% of IC patients showed serology results consistent with UC. CONCLUSIONS: Although this combination of serological markers provides a diagnostic tool with generally high specificities, the low sensitivities of these serologicat markers, most notably in terms of CD, preclude the possibility that they can replace the tools currently used for inflammatory bowel disease diagnosis and management. It is possible, however, that these serological markers may prove beneficial in the management of IC.