Rheumatoid Arthritis Diagnosis

Because rheumatoid arthritis (RA) affects each patient differently, there is no surefire way to determine whether someone has the disease. Doctors look at a combination of symptoms, blood tests, and X-rays to diagnose RA.

According to American College of Rheumatology standards, a person has RA if he or she meets at least four of the following seven criteria:

• Morning stiffness for at least an hour per day for six weeks straight
• Pain and swelling for six weeks straight in at least three of the following joints: knuckle, finger, wrist, elbow, knee, ankle, and toe
• At least one swollen area in the finger, wrist or hand for six weeks straight
• Equal symptoms in joints on both sides of the body  (i.e. left and right hands, left and right wrists, etc.) for six weeks straight
• Presence of rheumatoid nodules (hard lumps under the skin of the arms, wrists, or elbows; see RA Symptoms section)
• Positive blood test for rheumatoid factor (an antibody found in the blood of 70 to 80 percent of RA sufferers; see RA Tests section)
• X-ray showing damage to bones in the affected joints