If your symptoms are slightly different from those listed above, this may indicate that you have another joint condition. For example, prolonged joint stiffness in the morning can be a sign of rheumatoid arthritis.
Further tests – such as X-rays or blood tests – are not usually necessary to confirm a diagnosis of osteoarthritis, although they may be used to rule out other possible causes of your symptoms, such as rheumatoid arthritis or a fractured bone.
X-rays can also allow doctors to assess the level of damage to your joints, but this is rarely helpful as the extent of damage visible on an X-ray isn’t a good indicator of how severe your symptoms are.
Source: NHS UK