BASDAI (Ankylosing Spondylitis Disease Activity)
Bath Ankylosing Spondylitis Disease Activity Index (BASDAI, 0–10) from six 0–10 items (the two morning-stiffness items averaged); ≥ 4 suggests active disease.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Fatigue
- 4
- Spinal pain
- 6
- Peripheral joint pain/swelling
- 2
- Enthesitis
- 3
- Morning-stiffness severity
- 5
- Morning-stiffness duration
- 7
Result: BASDAI 4.2 — active disease (≥ 4).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Threshold
- BASDAI ≥ 4 suggests active / suboptimally controlled axial spondyloarthritis; below 4 is lower activity.
What you enter
- Fatigue (0–10)
- Spinal pain (0–10)
- Peripheral joint pain/swelling (0–10)
- Enthesitis (0–10)
- Morning-stiffness severity (0–10)
- Morning-stiffness duration (0–10)
How this is calculated
- Formula
- Six 0–10 items; BASDAI = [Q1 + Q2 + Q3 + Q4 + (Q5 + Q6)/2] / 5. The two morning-stiffness items (Q5, Q6) are averaged before being added, not summed flat.
Garrett S, Jenkinson T, Kennedy LG, Whitelock H, Gaisford P, Calin A. A new approach to defining disease status in ankylosing spondylitis: the Bath Ankylosing Spondylitis Disease Activity Index. J Rheumatol. 1994;21(12):2286-2291. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.