The Clinical Arthritis RulE (CARE)

Welcome to the Clinical Arthritis RulE (CARE) calculator!

This calculator estimates the risks of the presence of inflammatory arthritis based on the research of Ten Brinck et al. More information on this calculator can be found at the bottom of the page. The rule is developed for use in patients in whom GPs or other physicians doubt about the presence of inflammatory arthritis. The calculator estimates the risk of the presence of synovitis, detectable at joint examination by experienced rheumatologists.


Symptom duration:

Morning stiffness duration:

Number of patient-reported painful joints:

Patient-reported joint swelling:

Difficulty with making a fist:

This calculator has the option to calculate the risks of current inflammatory arthritis in settings with different pre-test probabilities (i.e. prevalences). The calculator was derived and validated in patients in whom GPs suspected inflammatory arthritis and in whom inflammatory arthritis was confirmed in 41% of cases. Data obtained in (other) GP practices suggested that the pre-test risk in patient with suspected inflammatory arthritis is approximately 20%. Therefore the calculator can also estimate the risk on inflammatory arthritis in this setting.

  1. 7
  2. 6
  3. 5
  4. 4
  5. 3
  6. 2
  7. 1
  8. 0
Predicted risk of inflammatory arthritis
  1. 72%
  2. 44%
  3. 25%
  4. 17%
  5. 5%
  6. 3%
  7. 1%