Osteoarthritis is usually diagnosed after your doctor has taken a careful history of your symptoms. A physical exam will be done. There are no definitive lab blood tests to make an absolute diagnosis of osteoarthritis. Certain tests, specifically x-rays of the joint, may confirm your doctor’s impression that you have developed osteoarthritis.

X-ray examination of an affected joint —A joint with osteoarthritis will have lost some of the normal space that exists between the bones. This space is called the joint space. This joint space is made up of articular cartilage, which becomes thin. There may be tiny new bits of bone (bone spurs) visible at the end of the bones. Other signs of joint and bone deterioration may also be present. ]]>X-rays]]> , however, may not show very much in the earlier stages of osteoarthritis, even when you are clearly experiencing symptoms.

]]>Arthrocentesis]]> —Using a thin needle, your doctor may remove a small amount of joint fluid from an affected joint. The fluid can be examined in a lab to make sure that no other disorder is causing your symptoms (such as ]]>rheumatoid arthritis]]> , ]]>gout]]> , infection).

Blood tests —Blood tests may be done to make sure that no other disorder is responsible for your symptoms (such as rheumatoid arthritis or other autoimmune diseases that include forms of arthritis). Researchers are also looking at whether the presence of certain substances in the blood might indicate osteoarthritis and help predict the severity of the condition. These substances include breakdown products of hyaluronic acid (a substance that lubricates joints) and a liver product called C-reactive protein.