CDAI (Clinical Disease Activity Index, rheumatoid arthritis)
Clinical Disease Activity Index for RA: the lab-free sum of SJC28, TJC28, and the patient and physician global VAS (0-76) (Aletaha 2005).
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Swollen-joint count
- 6
- Tender-joint count
- 8
- Patient global assessment
- 3
- Physician global assessment
- 2
Result: CDAI 19/76 — moderate disease activity (> 10–22).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Bands
- remission ≤ 2.8, low ≤ 10, moderate ≤ 22, high > 22.
- Where the bands come from
- Not from the paper that introduced the index — it closed by saying the activity cut-offs still had to be determined. Remission at 2.8 or less is the ACR/EULAR criterion; 10 and 22 came later.
What you enter
- Swollen-joint count (0-28)
- Tender-joint count (0-28)
- Patient global assessment (0-10 cm VAS)
- Physician global assessment (0-10 cm VAS)
How this is calculated
- Formula
- CDAI = SJC28 + TJC28 + patient global (0–10 cm) + physician global (0–10 cm), total 0–76. No acute-phase reactant, so it is scored at the bedside.
Citation
Aletaha D, Nell VPK, Stamm T, et al. Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score. Arthritis Res Ther. 2005;7(4):R796-R806. Remission at 2.8 or less: Studenic P, et al. Ann Rheum Dis. 2023;82(1):74-80. Read the sources: Aletaha 2005 (the index) ↗, Studenic 2023 (remission) ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.