Disease Activity Score on 28 joints for rheumatoid arthritis (Prevoo 1995).

What it is and when to use it

The DAS28 (Disease Activity Score in 28 joints) is a composite index that quantifies rheumatoid arthritis activity by combining the tender and swollen joint counts across 28 joints, an acute-phase reactant (ESR or CRP) and the patient's global health assessment on a visual analogue scale. It is used to monitor disease activity over time and to guide a treat-to-target strategy. It is one of the disease activity measures recommended by EULAR for monitoring rheumatoid arthritis.

How to interpret it

With the ESR-based version (DAS28-ESR), the conventional thresholds are: below 2.6 indicates remission; 2.6 to 3.2 (inclusive) low activity; above 3.2 and up to 5.1 (inclusive) moderate activity; and above 5.1 high activity. A reduction of more than 1.2 points is considered a clinically meaningful response. The CRP-based version (DAS28-CRP) tends to yield slightly lower values, so the same cut-offs are not fully interchangeable and it may underestimate activity near the remission threshold.

Limitations and when not to use it

Validated in adults with established rheumatoid arthritis; it is not intended for other arthropathies or for diagnosis. The 28-joint count excludes the ankles and feet, so it may underestimate activity in patients with predominantly foot involvement. The global and joint assessments have a subjective component, and comorbidities such as fibromyalgia or infection can raise ESR/CRP or pain and distort the score. It does not assess radiographic structural damage or long-term physical function.

Frequently asked questions

What is the difference between DAS28-ESR and DAS28-CRP?

They use different acute-phase reactants and different formulas; DAS28-CRP usually gives somewhat lower values, so the same version should be used consistently in a given patient for comparison.

What DAS28 value indicates remission?

A DAS28-ESR below 2.6 is considered remission under the conventional criteria.

Which joints are included in the 28-joint count?

Twenty-eight joints are assessed, counting both sides: shoulders (2), elbows (2), wrists (2), metacarpophalangeal (10), proximal interphalangeal joints of the hands including the thumb interphalangeal joint (10) and knees (2); the ankles and feet are excluded.