Lab Tests

For rheumatoid arthritis, since no single test definitively proves a patient has the disease, doctors generally rely on the patient's description of symptoms and the physical examination.

Your doctor may also order a laboratory test for rheumatoid factor, an antibody found in the blood of RA patients. However, rheumatoid factor is not always present in RA patients, and not all patients who test positive for this factor have RA.

In the Encyclopedia:

This article was reviewed and updated June 2007.