TESTS FOR RHEUMATOID ARTHRITIS

Your doctor may suspect rheumatoid arthritis based on your symptoms and physical examination.  A history of pain, swelling, and stiffness over several months, with obvious physical evidence of red, swollen, tender joints, can be highly suggestive of rheumatoid arthritis.  However, joint pain can have 200 or so causes, and although RA is common, it is just one of several possibilities.  Therefore, several tests are typically done to confirm RA and monitor you after diagnosis.  Here are some common examples of what your doctor is checking:

Rheumatoid Factor(RF):  The immune system makes RF during the malfunctioning that causes the body to attack its own joints.  RF is positive in about 60 percent of people with RA, typically in cases of disease with high activity. RF is also present in other conditions like lupus and Sjogrens disease. 

Anticyclic citrullinated peptide antibodies (anti-CCP):  anti-CCP is a relatively new test that provides doctors with another immune system marker to help diagnose and follow RA.

Inflammation markers:  Erythrocyte sedimentation test (ESR) and C-reactive protein (CRP) are common inflammatory markers.  They are elevated in RA as well as many different inflammatory conditions, so they are considered nonspecific.  However, they are useful to monitor changes in activity in RA, especially when trying different medication combinations. 

X-rays:  Imaging studies are generally important in any arthritis evaluation.  For RA, your doctor will be checking to see if you have developed any bony erosions that lead to joint destruction.  The goal of RA is to stop the disease from causing this to occur.  Occasionally, further imaging like MRI may be needed if there are unusual x-ray finding.

Joint fluid testing:  The fluid in swollen joints in RA have typical features that help confirm the diagnosis.  If your doctor is trying to figure out if your joint swelling is caused by RA, especially if there are other possibilities such as gout, infection, or osteoarthritis, fluid sampling can be very useful.