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.
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.