Paget's disease of bone can be diagnosed with a blood test and an X-ray or scan.

A simple blood test can be carried out to check the level of a substance called alkaline phosphatase (ALP) in your blood.

People with Paget's disease of bone often have raised levels of ALP, although some people with the condition have a normal ALP level and a high level can also be caused by some other conditions.

An X-ray or scan is therefore also needed to confirm the diagnosis.

An X-ray can show whether your bones have become enlarged as a result of Paget's disease of bone.

A bone scan called scintigraphy is also usually done to check how much of your body is affected by the condition.

For this scan, a small amount of a radioactive substance is injected into your blood. This collects in areas where there's a lot of bone renewal taking place.

A gamma camera is then used to detect the radiation and highlight affected parts of the body.

Further tests are usually only needed if your diagnosis is not clear, or if you may have complications.

In these cases, you may be advised to have a:

• bone biopsy – a sample of bone is removed under anaesthetic so it can be looked at in detail
• CT scan – a series of X-rays of the affected bone are taken to create a detailed 3-dimensional image
• MRI scan – a strong magnetic field and radio waves are used to create an image of the affected bone