During the physical exam, your doctor will check your affected joint for tenderness, swelling, redness and flexibility.
Imaging tests:
To get pictures of the affected joint, your doctor might recommend:
• X-rays: Cartilage doesn't show up on X-ray images, but cartilage loss is revealed by a narrowing of the space between the bones in your joint. An X-ray can also show bone spurs around a joint.
• Magnetic resonance imaging (MRI): An MRI uses radio waves and a strong magnetic field to produce detailed images of bone and soft tissues, including cartilage. An MRI isn't commonly needed to diagnose osteoarthritis but can help provide more information in complex cases.
Lab tests:
Analysing your blood or joint fluid can help confirm the diagnosis.
• Blood tests: Although there's no blood test for osteoarthritis, certain tests can help rule out other causes of joint pain, such as rheumatoid arthritis.
• Joint fluid analysis: Your doctor might use a needle to draw fluid from an affected joint. The fluid is then tested for inflammation and to determine whether your pain is caused by gout or an infection rather than osteoarthritis.
Courtesy: Mayo Clinic