Disease Activity Score 28-Joint (DAS28)
28-Joint Disease Activity Score for Rheumatoid Arthritis · Also known as: DAS28, DAS28-CRP, DAS28-ESR
The DAS28 is a composite measure of rheumatoid arthritis (RA) disease activity, combining joint counts, inflammatory markers, and patient-reported global health. Developed in 1995 by Prevoo and colleagues, it has become the gold standard for monitoring RA activity in clinical trials and practice. It integrates objective clinical signs with laboratory and subjective assessment, providing a single numerical index of disease burden.
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When to use it
DAS28 is the primary tool for assessing RA disease activity in clinical practice and trials. Use at baseline, regular intervals during treatment (typically every 3 months), and at critical decision points (response failure, remission achieved). It is appropriate for patients aged ≥18 years with suspected or confirmed RA. DAS28 is less sensitive in seronegative RA and limited to 28 joints; clinicians may prefer DAS44 (44-joint version) or Boolean remission criteria when additional small joints are affected. Not suitable for diseases outside RA (though similar measures exist for other inflammatory arthropathies).
Strengths & limitations
- Extensively validated composite index with strong predictive validity for radiographic damage and disability progression.
- Combines objective joint examination, laboratory marker, and patient perspective—balancing clinician judgment with biomarkers.
- Simple calculation via online calculator or mobile app; reproducible across trained assessors.
- Standardised cutoffs and EULAR response criteria enable consistent communication in trials and inter-centre comparisons.
- ESR and CRP variants allow flexibility based on available testing; CRP responds faster to treatment.
- Sensitive to change; MCID well-established, making it suitable for detecting clinically meaningful improvements or deterioration.
- Limited to 28 joints; may underestimate activity in patients with predominant small-joint or axial involvement (e.g., feet, ankles).
- Does not include function, radiographic damage, or systemic features (e.g., nodules, vasculitis)—requires separate assessment.
- Dependent on ESR or CRP availability; not all patients have concurrent lab testing at clinical visits.
- ESR is non-specific and increases with age, anaemia, and infection unrelated to RA activity.
- Requires trained examiner; inter-rater variability possible without standardisation.
- Does not capture remission in the modern treat-to-target era (many patients below DAS28 <2.6); Boolean or SDAI remission criteria may be more informative.
Frequently asked
What is the difference between DAS28-ESR and DAS28-CRP?
Both are valid and highly correlated. The ESR variant uses erythrocyte sedimentation rate; CRP variant substitutes C-reactive protein (0.36ln(CRP+1) instead of 0.70ln(ESR)). CRP changes more rapidly with treatment (within days), while ESR changes more slowly. Choose CRP if rapid response monitoring is desired, or ESR if CRP is unavailable. Both are acceptable for remission definitions.
Can DAS28 be used to diagnose rheumatoid arthritis?
No. DAS28 measures disease activity in patients with established or suspected RA. Diagnosis requires clinical examination, serology (RF, anti-CCP), and imaging per ACR/EULAR criteria. DAS28 is a monitoring tool, not a diagnostic tool.
What does a DAS28 score of 3.8 mean?
A DAS28 of 3.8 indicates moderate disease activity (>3.2 and ≤5.1). This suggests clinically apparent synovitis with ongoing inflammatory burden and risk of radiographic progression if untreated. Most rheumatologists would consider dose escalation or therapy switch if this persists beyond 3 months.
How often should DAS28 be assessed?
Baseline before treatment initiation, then every 4–12 weeks during treatment titration (more frequently if unstable), and every 3–6 months once stable remission is achieved. Some treat-to-target protocols use monthly assessments until remission is reached. Annual or longer intervals are acceptable for patients in sustained remission.
Is DAS28 <2.6 the same as remission?
DAS28 <2.6 indicates remission by DAS28 definition, but stricter Boolean (SJC=0, TJC=0, CRP ≤1 mg/dL, global <1 on 0–10) and SDAI (SDAI ≤3.3) remission criteria are now preferred in treat-to-target protocols. Many patients with DAS28 <2.6 have low-grade inflammation detectable by ultrasound or MRI. Modern guidelines favour combined assessments.
What causes a discrepancy between joint count and DAS28?
If joints appear only mildly swollen but ESR/CRP is high, DAS28 may not reflect the examiner's clinical impression (square-root transformation emphasises fewer joints more than many mildly swollen joints). Conversely, high joint counts with normal labs yield higher DAS28. Consider clinical context, imaging, and biomarkers; DAS28 should not override clinical judgment alone.
Can DAS28 be used in non-RA arthropathies?
DAS28 is validated only for RA. Analogous measures exist for other conditions (BASDAI for ankylosing spondylitis, SLEDAI for lupus). Do not apply DAS28 to psoriatic arthritis, seronegative spondyloarthropathy, or other non-RA conditions without validation study evidence.
What if a patient has only a few swollen joints but high ESR?
DAS28 will reflect both the low joint count (contributing less after square-root transformation) and high ESR (contributing substantially). This may occur in early RA with limited polyarticular involvement but systemic inflammation, or with concurrent infection/comorbidity raising ESR. Integrate clinical judgment; consider imaging to confirm synovitis and re-examine joints carefully.
Sources
- Prevoo ML, Hart's AM, Van Houwelingen HC, et al. Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis & Rheumatism. 1995;38(1):44-48. DOI: 10.1002/art.1780380107 ↗
How to cite this page
ScholarGate. (2026, June 3). 28-Joint Disease Activity Score for Rheumatoid Arthritis. ScholarGate. https://scholargate.app/en/rheumatology/das28
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
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