Crohn's Disease Activity Index (CDAI)

Assess disease activity in Crohn's disease


The Crohn's Disease Activity Index (CDAI) is utilized in clinical trials to assess disease activity in Crohn's.

CDAI scores can range from 0 to ~600.

A cut-off value of <150 was selected so that most patients below this threshold would be rated by physicians as 'very well'.

The delineator between active and very severe disease was defined as a cut-off value of 450 points.

CDAI scores of 150–219 has been labelled as mildly active disease and scores of 220–450 as moderately active disease.

CDAI has some limitations, which include:

  • interobserver variability
  • ratings of 'general well being' and 'intensity of abdominal pain' are subjective
  • stool frequency is based on a diary filled in by the patient for 7 days before evaluation which doesn't generally get done in routine clinical practice
  • it is not accurate in patients with fistulizing and stenosing disease
  • it is not useful in patients with previous extensive ileo-colonic resections or stoma


Best WR.

nflammatory Bowel Diseases 2006, 12 (4): 304-10

Best WR, Becktel JM, Singleton JW, Kern F Jr.

Gastroenterology 1976, 70 (3): 439-44

The Crohn's Disease Activity Index (CDAI) calculator is created by QxMD.

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1. Average Number of Liquid or Soft Stools per Day (over 7 days)?

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