ASDAS calculator
Ankylosing Spondylitis Disease Activity Score — CRP and ESR versions, with the 2018 disease activity states.
Result
Disease activity states (2018 update)
| State | ASDAS |
|---|---|
| Inactive disease | < 1.3 |
| Low disease activity | 1.3 – < 2.1 |
| High disease activity | 2.1 – 3.5 |
| Very high disease activity | > 3.5 |
Improvement: a decrease of ≥ 1.1 is clinically important; ≥ 2.0 is major improvement.
Formulas
ASDAS-CRP = 0.12×Back pain + 0.06×Morning stiffness duration + 0.11×Patient global + 0.07×Peripheral pain/swelling + 0.58×ln(CRP+1)
ASDAS-ESR = 0.08×Back pain + 0.07×Morning stiffness duration + 0.11×Patient global + 0.09×Peripheral pain/swelling + 0.29×√ESR
Lukas C, et al. Ann Rheum Dis 2009;68:18–24; Machado PM, et al. Ann Rheum Dis 2018;77:1539–40 (updated cut-offs). CRP in mg/L; values below 2 mg/L are replaced by 2 (Machado P, et al. Ann Rheum Dis 2015;74:1758–9 / ASAS handbook).
For healthcare professionals. This calculator supports, and does not replace, clinical judgement. Classification criteria are designed for research cohorts and are not diagnostic criteria. Check results against the source publication before acting on them.
Referring a patient?
Walk-in rheumatology OPD at AIMS Mohali — no appointment needed. A short referral note with recent results helps.
Clinic timings & location