Arthritis - Diagnosis
Rheumatoid arthritis and osteoarthritis are usually both diagnosed based on a patient's history. This history typically includes an increasing occurrence of pain and stiffness in joints. The doctor can also examine the patient's affected joint for swelling, limitations on movement, pain, and a cracking sound that is sometimes heard with a damaged joint.
There are no blood tests that strongly confirm the presence of arthritis. Many tests that can be used for RA are also positive for other disorders. One test measures the amount of a chemical known as rheumatic factor in a patient's blood. Rheumatic factor is produced by the immune system when it attacks a joint. It is found in about 66 percent of patients with RA. But it is also found in 10 to 20 percent of healthy people over the age of sixty.
A good diagnosis for OA can sometimes be obtained from X rays or other imaging techniques. An X-ray photograph may show changes in the space between bones in a joint, indicating the presence of OA.