Enter 7-day symptoms and measurements
Example data table
| Scenario | Stools (7d) | Pain avg | Well avg | Complications | Antidiarrheal | Mass | Sex/Hct | Wt/Std | CDAI | Category |
|---|---|---|---|---|---|---|---|---|---|---|
| Sample A | 21 | 1.0 | 1.5 | 1 | No | 0 | M/40 | 62/70 | ~244 | Moderate activity |
| Sample B | 7 | 0.3 | 0.4 | 0 | No | 0 | F/41 | 58/58 | ~77 | Remission |
Formula used
The Crohn Disease Activity Index is the weighted sum of eight weekly components:
- 2 × total number of liquid/soft stools over 7 days
- 5 × sum of daily abdominal pain ratings (0–3) over 7 days
- 7 × sum of daily well-being ratings (0–4) over 7 days
- 20 × number of complications present during the week
- 30 × antidiarrheal use during the week (0 or 1)
- 10 × abdominal mass score (0, 2, or 5)
- 6 × (hematocrit reference − measured hematocrit)
- 1 × percent weight deviation: (1 − weight/standard) × 100
Severity bands commonly used: <150 remission, 150–219 mild, 220–450 moderate, >450 severe. Many studies define response as a drop of ≥70 or ≥100 points versus baseline.
How to use this calculator
- Collect stool counts and daily ratings for the last 7 days.
- Enter complications, antidiarrheal use, abdominal mass, hematocrit, and weights.
- Press Calculate CDAI to see the score and component breakdown.
- Optionally enter a prior score to estimate change over time.
- Use CSV/PDF exports for tracking and discussions with your care team.
FAQs
1) What is the CDAI used for?
It is a structured symptom-based index often used in research studies and monitoring. It helps quantify symptom burden over one week and compare changes over time.
2) Does this score diagnose Crohn’s disease?
No. It summarizes reported symptoms and select measurements. Diagnosis and treatment decisions require clinical assessment, tests, and professional judgment.
3) Why are there daily entries for seven days?
The index is defined over a 7-day window. Daily entries reduce noise from day-to-day variation and better represent an overall weekly pattern.
4) What counts as a complication here?
The list covers common extraintestinal or perianal findings used in the index. Each checked item is counted once for that week, then weighted in the score.
5) How should I choose “standard weight”?
Some protocols use a reference or ideal weight. If you know a reference value from your records, enter it directly. The height-based helper is only a convenience estimate.
6) Why are there “clamp negative” options?
If hematocrit or weight exceed the reference, the raw formula can subtract points. Some implementations clamp negative deviations to zero for simplicity. Choose the option that matches your intended protocol.
7) What do the severity categories mean?
They are commonly used thresholds: below 150 suggests remission; 150–219 mild activity; 220–450 moderate activity; above 450 severe activity. Interpret them in clinical context.
8) Can I use this to track response to treatment?
You can compare scores over time. Many studies consider a decrease of 70–100 points as a meaningful response, but this depends on the study and individual situation.