Free Papers

Objective: To assess the diagnostic precision of antiSaccharomyces cerevisiae (ASCA) and perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) in inflammatory bowel disease(IBD) and evaluate their discriminative ability between ulcerative colitis(UC) and Crohn’s disease(CD). Method: Meta-analysis of studies reporting on ASCA and pANCA in IBD was performed. Sensitivity, specificity and likelihood ratios (LR+, LR)) were calculated for test combinations for CD, UC and for IBD compared to controls. Meta-regression was used to analyse the effect of age, colonic CD and assay type. Results: Sixty studies comprising 3841 UC and 4019 CD patients were included. The ASCA+ve with pANCA-ve test offered the best sensitivity for CD(54.6%) with 92.8% specificity, area under the ROC curve (AUC) of 0.85; (LR+ = 6.5, LR– = 0.5). Sensitivity and specificity of pANCA+ve tests for UC were 55.3% and 88.5% respectively, (AUC of 0.82; LR+ = 4.5, LR– = 0.5). Sensitivity and specificity was improved to 70.3% and 93.4% in a paediatric subgroup when combined with an ASCA-ve test. Meta-regression analysis showed decreased diagnostic precision of ASCA for isolated colonic CD (RDOR = 0.3). Conclusion: ASCA and pANCA testing is specific but not sensitive for CD and UC. It may be particularly useful for differentiating between CD and UC in the paediatric population.