Diagnosis is based on a wide range of evidence.

There is no specific test for OA. A complete clinical assessment will include a discussion of any family history of OA, and a physical examination to identify misalignment, deformities, mechanical problems and which joints are affected.

OA is often visible on X-ray, and that can confirm that the pain and stiffness is indeed due to OA. X-ray can be useful in uncovering subtitle joint abnormalities and other joint and bone diseases, like osteoporosis. However, X-ray may not pick up early arthritic changes, even if there are symptoms.