DAS28 Calculator — Rheumatoid Arthritis Disease Activity Score (ESR or CRP)
Calculate the DAS28 rheumatoid arthritis activity score with ESR or CRP from 28 tender and swollen joint counts and patient global health — remission, low, moderate or high activity.
How it works
DAS28-ESR = 0.56·√TJC28 + 0.28·√SJC28 + 0.70·ln(ESR) + 0.014·GH. DAS28-CRP = 0.56·√TJC28 + 0.28·√SJC28 + 0.36·ln(CRP + 1) + 0.014·GH + 0.96 (CRP in mg/L, GH 0–100 mm). Activity: < 2.6 remission · 2.6–3.2 low · > 3.2–5.1 moderate · > 5.1 high.
The Disease Activity Score in 28 joints (Prevoo et al., 1995) is the standard composite measure of rheumatoid arthritis activity used in clinics, treat-to-target strategies and trials. It combines the tender and swollen counts of 28 joints (shoulders, elbows, wrists, knuckles, finger joints and knees), an inflammatory marker and the patient’s global assessment on a 100 mm scale. The EULAR cut-offs define remission below 2.6, low activity up to 3.2 and high activity above 5.1. DAS28-CRP tends to read lower than DAS28-ESR in the same patient, so use the same version over time.
Worked example
A patient has 6 tender and 4 swollen joints, an ESR of 30 mm/h and rates global health 50 / 100: DAS28-ESR = 0.56·√6 + 0.28·√4 + 0.70·ln 30 + 0.014·50 = 1.37 + 0.56 + 2.38 + 0.70 = 5.01 — moderate disease activity. With a CRP of 10 mg/L the DAS28-CRP would be 4.45.
Sources: Prevoo ML et al. Modified disease activity scores that include twenty-eight-joint counts. Arthritis Rheum 1995 · DAS-score.nl — Disease Activity Score in rheumatoid arthritis (Radboud University)
Frequently asked questions
What DAS28 score is remission?
A DAS28 below 2.6 is classed as remission, 2.6–3.2 low disease activity, above 3.2 up to 5.1 moderate and above 5.1 high disease activity.
Which 28 joints are counted?
Both shoulders, elbows, wrists and knees, the 10 knuckles (MCP joints) and the 10 middle finger joints (PIP joints, including the thumb interphalangeal joints). Feet and ankles are not included.
Should I use DAS28-ESR or DAS28-CRP?
Either is valid, but they are not interchangeable — DAS28-CRP usually gives lower values. Use the version your clinic uses and keep to it when tracking a patient over time.
What change in DAS28 is meaningful?
Under the EULAR response criteria, a fall of more than 1.2 is a meaningful improvement; a fall of 0.6 or less is no response.
Related calculators
Clinical decision tool for education and for use by trained clinicians alongside clinical judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.