Introduction: In inflammatory bowel disease (IBD), commonly used biomarkers employed for non-invasive monitoring of disease activity are the C-reactive Protein (CRP) and Erythrocyte Sedimentation Rate (ESR). Ulcerative colitis (UC) has a modest to absent CRP response despite active inflammation. Iron deficiency anaemia (IDA) is often a marker of active disease in IBD. Methods: CRP, ESR, and Haemoglobin level taken within 7 days of a colonoscopy were analysed and compared with histopathological findings from colonic and ileal biopsies. Results: Colonic biopsies from 95 colonoscopies in UC patients; and colonic and ileal biopsies from 98 colonoscopies in CD patients were analyzed. The Positive Predictive Values and Negative Predictive Values relating to ESR, CRP and iron deficiency anaemia in the two groups of patients were calculated. Conclusion: UC has a similar CRP response to CD in active inflammation. Commonly used biomarkers have poor sensitivities in demonstrating active mucosal disease. IDA has little value when used as a marker of disease activity on its own but may be used as an adjunct to ESR and CRP. Faecal biomarkers and novel antibodies may help to increase the sensitivity and specificity in non-invasive monitoring of IBD.peer-reviewe
