Patients displaying symptoms of psoriatic arthritis may undergo more testing to eliminate the source of their joint inflammation from other forms of arthritis, such as rheumatoid arthritis, which carries a different type of antibody in the blood than psoriatic arthritis.

One such test is the erythrocyte sedimentation rate, or ESR. This test determines how quickly red blood cells settle within an hour. This is used to differentiate between different causes of inflammation. A simple blood draw is all that is needed from the patient to administer the test.

Your doctor may order x-ray examinations of your joints to further rule out any other conditions, such as broken or fractured bones or strained or sprained joints. Arthritis of the joints can also be seen on a simple x-ray.

Your doctor may also take a blood sample to test which kind of therapy might be best for you.