Psoriatic Arthritis
Diagnosis

Your doctor will begin by recording your complete medical history and asking you to describe your symptoms. Then you will undergo a physical examination, during which your doctor will look for any physical signs of the disease. The following tests also may be recommended to help make a definite diagnosis:

• Erythrocyte sedimentation rate. This is a common blood test that is used to detect and monitor inflammation in the body.
• Rheumatoid factor. This blood test detects an antibody that is present in the blood of most patients with rheumatoid arthritis. It is conducted to exclude rheumatoid arthritis.
• Arthrocentesis. This is an office procedure during which a sterile needle is used to withdraw fluid from the inflamed joints. The fluid is then analyzed for infection, gout crystals and other inflammatory conditions.
• X-rays. These may show characteristic changes associated with arthritis in the spine, sacrum, and joints of the extremities.