CDAI Calculator
Calculate the Crohn's Disease Activity Index (CDAI) — the most widely used measure of Crohn's disease severity in clinical trials.
What is CDAI?
The Crohn's Disease Activity Index (CDAI), developed by Best and colleagues in 1976, combines patient-reported symptoms, clinical findings and a hematocrit deviation into a single score. It remains the dominant outcome measure in Crohn's disease clinical trials. Scores below 150 indicate clinical remission; 150–219 mild activity; 220–449 moderate-severe; ≥ 450 severe-fulminant.
How is it calculated?
The 8-component formula: 2 × (liquid stools, sum) + 5 × (abdominal pain) + 7 × (general well-being) + 20 × (complications) + 30 × (antidiarrhoeal use) + 10 × (abdominal mass) + 6 × (hematocrit deviation) + 1 × (weight deviation %).
Frequently Asked Questions
- Is CDAI used in the clinic?
- More often in trials; the simpler Harvey-Bradshaw Index is common in clinical practice.
- Can patients calculate it?
- With training, yes — the diary aspect is patient-reported.
- Is CDAI < 150 clinical remission?
- Yes, by the conventional trial definition.
- Does CDAI track mucosal healing?
- Imperfectly — endoscopy and imaging are more direct.