Your doctor may suspect rheumatoid arthritis (RA) based on your symptoms. Diagnosing RA can sometimes be difficult since there are several autoimmune disorders that have similar symptoms. Part of diagnosing RA is ruling out these other disorders.
The American College of Rheumatology and the European League Against Rheumatism have created a system for diagnosing RA. To start, symptoms need to be present for 6 weeks or more. The system then uses a 10-point scale assessing specific symptoms. The higher the score, the more likely RA is present.
Considered factors include:
The number of sore or swollen joints and any associated damage is considered. The areas affected may be a small joint ( hands or feet) or a large joint (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.
Blood tests look for markers of RA. Specific substances that may be present with RA can be found in the blood. These include:
Imaging tests assess the joints, surrounding structures, and any associated damage. Tests may include:
The following tests involve tissue samples. The samples are examined under a microscope. They can help diagnose RA (and other conditions).
Rheumatoid arthritis. Arthritis Foundation website. Available at: http://www.arthritis.org/about-arthritis/types/rheumatoid-arthritis. November 29, 2016.
Rheumatoid arthritis. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/musculoskeletal-and-connective-tissue-disorders/joint-disorders/rheumatoid-arthritis-ra. Updated August 2015. Accessed November 29, 2016.
Rheumatoid arthritis. National Institute of Arthritis and Musculoskeletal and Skin Diseases website. Available at: http://www.niams.nih.gov/Health_Info/Rheumatic_Disease/default.asp. Updated February 2016. Accessed November 29, 2016.
Rheumatoid arthritis (RA). EBSCO DynaMed Plus website. Available at:http://www.dynamed.com/topics/dmp~AN~T115261/Rheumatoid-arthritis-RA. Updated September 30, 2016. Accessed October 4, 2016.
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9/10/2010 DynaMed Plus Systematic Literature Surveillancehttp://www.dynamed.com/topics/dmp~AN~T115261/Rheumatoid-arthritis-RA: Aletaha D, Neogi T, Silman AJ, et al. 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Ann Rheum Dis. 2010;69(9):1580-1588.
Last reviewed November 2016 by Michael Woods, MD Last Updated: 5/20/2015