CDAI Score Calculator

CDAI Score Calculator for Rheumatology. CDAI remission is at or below 2.8; low activity is above 2.8 through ten, moderate above ten through 22, and high above 22. A value of 2.805 is low activity even when display rounding makes it look close to remission.

For shared guidance on choosing a tool and documenting results, read the clinical calculator workflow.

How this calculator works

The rheumatoid arthritis Clinical Disease Activity Index adds tender joints, swollen joints, patient global and evaluator global. It omits laboratory inflammatory markers. It is unrelated to the Crohn Disease Activity Index that happens to share the same abbreviation.

When to use this calculator

Use the RA index for an activity assessment when the clinician and patient ratings are available at the visit. Maintain consistent joint examination and global-assessment scale conventions when following change across appointments.

Inputs used

  • Whole-number tender and swollen counts from the standard 28-joint examination, plus patient and evaluator global activity assessments on 0-10 scales.

Clinical interpretation

CDAI remission is at or below 2.8; low activity is above 2.8 through ten, moderate above ten through 22, and high above 22. A value of 2.805 is low activity even when display rounding makes it look close to remission.

Worked example

Tender count one, swollen count one, patient global four and evaluator global three give CDAI nine. A CRP value does not alter this result; adding CRP would instead calculate SDAI and requires that separate method and its cutoffs.

Limitations and safety notes

The index ranges from zero to 76. It does not assess all joints or establish the cause of pain. Lack of a CRP requirement is convenient but does not mean laboratory testing is clinically unnecessary. Treatment decisions need the full assessment.

References

  • https://pmc.ncbi.nlm.nih.gov/articles/PMC4028066/

Editorial review and citation methodology

Maintained by the Quick Medical Calculator Editorial Team. Content record date: September 9, 2026. A content date is not evidence of independent clinical review. Individual clinical sign-off is not recorded on this page.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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