Osteoarthritis

Laboratory Tests
There is no specific laboratory test to diagnose OA. It is diagnosed by a doctor using a patient’s medical history, a physical exam, X-rays, and in some cases with an examination of synovial fluid from an affected joint. Tests that may be ordered to rule out other conditions and to evaluate the patient’s health include:

• Rheumatoid factor (RF) and Cyclic Citrullinated Peptide Antibody (CCP) – used to help diagnose rheumatoid arthritis and differentiate it from osteoarthritis.
• Synovial fluid analysis – to detect crystals that may be present in the joint and to look for signs of joint infection.
• Erythrocyte sedimentation rate (sed rate or ESR) – this test shows the presence of inflammation in the body. ESR will be increased in RA but not in osteoarthritis.
• C-reactive protein test (CRP) —this test also indicates inflammation and tests for the activity of the disease. It may be used to help differentiate osteoarthritis and RA. An increased level of CRP occurs in RA but not in osteoarthritis.
• Complete Blood Count (CBC) – this is a group of tests that are used to help evaluate the patient’s red and white blood cells and hemoglobin. It may be ordered to monitor the side effects of some OA treatments.
• Comprehensive Metabolic Panel (CMP) – this is a group of tests that may be used to help evaluate and monitor the patient’s kidney and liver function.

Non-Laboratory Tests

• X-rays of the affected joints may show loss of cartilage and narrowing of the joint space but will frequently not show significant changes early in the disease.
• MRI (magnetic resonance imaging) – may also be used to examine affected joints.