Mayo Clinic Health Manager
Get free personalized health guidance for you and your family.
Get Started
About our e-newsletters
- Free e-newsletters
- Mayo Clinic expertise
- We do not share your e-mail address
Housecall, our weekly general-interest e-newsletter, keeps you up to date on a wide variety of health topics with timely, reliable, practical information, recipes, blogs, questions and answers with Mayo Clinic experts and more. Our biweekly topic-specific e-newsletters also include blogs, questions and answers with Mayo Clinic experts, and other useful information that will help you manage your health.
Housecall Archives
Mayo Clinic Housecall
Stay up to date on the latest health information.
What you get
- Free weekly e-newsletter
- Mayo Clinic expertise
- Recipes, tools and other helpful information
- We do not share your e-mail address
Tests and diagnosis
By Mayo Clinic staffNo single test can confirm a diagnosis of psoriatic arthritis. Your doctor will assess your signs and symptoms and work to rule out other causes of joint pain, such as osteoarthritis and rheumatoid arthritis. Tests that help to distinguish psoriatic arthritis from other conditions include:
- X-rays. These can help pinpoint changes in the joints that occur in psoriatic arthritis but not in other arthritic conditions.
- Joint fluid test. In this test, your doctor removes a small sample of fluid from one of your joints — often the knee — for analysis in a laboratory. Uric acid crystals in your joint fluid may indicate that you have gout, rather than psoriatic arthritis.
- Sed rate. This blood test checks your erythrocyte sedimentation rate (ESR), commonly known as the sed rate, by measuring how far from the top of a glass tube your red blood cells fall in a given time. Generally, the blood cells fall faster and farther — that is, the sed rate increases — when inflammation is present. But because many conditions can cause inflammation in the body, including many forms of arthritis and other rheumatic diseases, an elevated sed rate alone can't confirm the presence of psoriatic arthritis.
- Rheumatoid factor (RF). RF is an antibody — a protein made by the immune system — that's often present in the blood of people with rheumatoid arthritis, but not in the blood of people with psoriatic arthritis. For that reason, this test can help your doctor distinguish between the two conditions.
- Questions and answers about psoriasis. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/hi/topics/psoriasis/psoriafs.htm. Accessed Sept. 9, 2008.
- Psoriatic arthritis. American College of Rheumatology. http://www.rheumatology.org/public/factsheets/psoriatic_new.asp. Accessed Sept. 9, 2008.
- Psoriasis of the nails. National Psoriasis Foundation. http://www.psoriasis.org/about/psoriasis/sites/nails.php. Accessed Sept. 9, 2008.
- Psoriatic arthritis. National Psoriasis Foundation. http://www.psoriasis.org/about/psa. Accessed Sept. 9, 2008.
- Gordon KB, et al. The treatment of psoriasis and psoriatic arthritis: An interdisciplinary approach. The Journal of the American Academy of Dermatology. 2006;54(3)(suppl):S85-S91.
- Cerhan JR, et al. Antioxidant micronutrients and risk of rheumatoid arthritis in a cohort of older women. American Journal of Epidemiology. 2003;157(4):345-354.
- Imokawa S, et al. Methotrexate pneumonitis: Review of the literature and histopathological findings in nine patients. The European Respiratory Journal. 2000;15(2):373-381.
- Tobin AM, et al. TNF alpha inhibitors in the treatment of psoriasis and psoriatic arthritis. BioDrugs. 2005;19(1):47-57.
- Gladman DD, et al. Patient information: Psoriatic arthritis. http://www.uptodate.com/home/index.html. Accessed Sept. 11, 2008.
