Clinical Disease Activity Index for RA (CDAI)

Assess disease activity in rheumatoid arthritis, without requiring lab work.


Clinical disease activity index (CDAI) is a simplification from the SDAI as it does not require the measurement of an acute phase reactant. Otherwise, it uses the same clinical assessments as the SDAI.

The CDAI correlates well with other disease activity scores and response criteria, as well as with progression of joint damage and functional impairment.

CDAI allows immediate treatment decisions to be based entirely on clinical criteria.

CDAI is calculated as follows:



  • SJC = Swollen Joint Count
  • TJC = Tender Joint Count
  • PGA = Patient Global Assessment of Disease Activity
  • EGA = Evaluator Global Assessment of Disease Activity


  • ≤2.8: Remission
  • >2.8 and ≤10: Low Disease Activity
  • >10 and ≤22: Moderate Disease Activity
  • >22: High Disease Activity

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1. Swollen Joint Count?

More Information

28 joints are assessed, including:

Shoulders, Elbows, Knees
In the hands: first through fifth metacarpophalangeal joint, the interphalangeal joint of the thumb, and the second through fifth proximal interphalangeal joint.

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