Commentary: irritable bowel syndrome and the CDAI - misleading activity by straw men; authors’ reply

contrast, more objective measures, such as C-reactive protein (CRP) and haematocrit score, were, as one would predict, higher in Crohn’s patients. It is important to note that one half of all Crohn’s patients in this study appeared to be ‘active’ so one must be cautious in interpreting the application of their findings to Crohn’s patients in true remission. So where does this leave us? First and foremost, CDAI was never designed as a diagnostic tool for Crohn’s disease; to suggest otherwise is to erect a straw man. Its value lies in assessing the patient’s symptomatic response to treatment (we are, after all, treating patients, not blood tests or radiological images alone), but seems incapable, when expressed as a total score, of differentiating IBS from IBD; again no surprise. We contend that ‘IBStype symptoms’ in IBD should be regarded as representing IBD activity until proven otherwise. 6 In most instances, the differentiation is obvious; when uncertainty persists, sensitive biomarkers such as faecal calprotectin may be helpful.