The American College of Rheumatology and the European League Against Rheumatism have created a system for diagnosing rheumatoid arthritis (RA). One of the main criteria is that you have to have at least one swollen or tender joint or a history of a swollen joint. The areas affected may be small joints (eg, located in the hands or feet) or a large joint, like the ones found in the shoulders, elbows, hips, knees, or ankles. Which joints are affected, how many joints are affected, and for how long they have been affected all help with the diagnosis.

The following blood tests are also done to help with the diagnosis:

    
  • Rheumatoid factor (RF)
  • Anti-citrullinated protein antibody
  • Erythrocyte sedimentation rate (ESR)
  • C-reactive protein (CRP)
  • In addition, imaging tests, like x-rays , ultrasounds, or MRI scans may be ordered to get more information about your joints.

    Your doctor will also rule out other conditions that have similar symptoms to RA. Examples of these other conditions include:

        
  • Fibromyalgia
  • Osteoarthritis
  • Gout
  • Lupus