<prompt> In case of acute severe colitis on day 3 of hospital , the best predictor of colectomy is:CRP 45 mgL and 3-8 stool frequencyESR 60 mm Hg and abdominal painBleeding PR and abdominal distentionTachycardia and fever  <response>: C-reactive protein is a less good marker for assessing disease activity in UC than Crohns disease. In acute severe colitis a raised CRP 45 mgL on day 3 following hospital admission together with 3-8 stools a day is highly predictive for colectomy. Ref: Journal of Crohns and Colitis 2012 6, 965-990. 