Calculators · Rheumatology · Score

ASDAS-ESR (Ankylosing Spondylitis Disease Activity Score)

Also called ASDAS ESR

Alternative ASDAS using ESR when CRP is not available.

0–10
0–10
0–10
0–10
mm/h

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Formula and scoring

ASDAS-ESR = 0.08·back pain + 0.07·morning stiffness duration + 0.11·patient global + 0.09·peripheral pain/swelling + 0.29·√ESR (mm/h).

Exam and ward pearls

  • Cut-offs 1.3, 2.1 and 3.5 separate the four states; the 1.3–2.1 band was renamed "low" (from "moderate") in the 2018 ASAS update.
  • A fall of ≥1.1 units is a clinically important improvement; a fall of ≥2.0 is a major improvement (Machado 2011).

When not to rely on it

  • Do not mix ASDAS-CRP and ASDAS-ESR values when following one patient over time.

Source

  1. Lukas C, Landewé R, Sieper J, et al. Development of an ASAS-endorsed disease activity score (ASDAS) in patients with ankylosing spondylitis. Ann Rheum Dis. 2009;68(1):18-24. doi:10.1136/ard.2008.094870 · PMID 18625618
  2. Machado P, Landewé R, Lie E, et al. Ankylosing Spondylitis Disease Activity Score (ASDAS): defining cut-off values for disease activity states and improvement scores. Ann Rheum Dis. 2011;70(1):47-53. doi:10.1136/ard.2010.138594 · PMID 21068095
  3. Machado PM, Landewé R, van der Heijde D. Ankylosing Spondylitis Disease Activity Score (ASDAS): 2018 update of the nomenclature for disease activity states. Ann Rheum Dis. 2018;77(10):1539-40. doi:10.1136/annrheumdis-2018-213184 · PMID 29453216
  4. Assessment of SpondyloArthritis international Society (ASAS). ASDAS calculator: formulae, CRP rule and disease activity states. Link

Formula and cut-offs checked against these sources on 8 Nov 2026. Educational tool for clinicians; it does not replace clinical judgement.

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