There's no single test for complex regional pain syndrome (CRPS). It's usually diagnosed by ruling out conditions with similar symptoms.

Some of the tests you may have to rule out other conditions can include:

• blood tests to rule out an underlying infection or rheumatoid arthritis
• an MRI scan to rule out underlying problems with your tissue or bones
• an X-ray to rule out problems with the joints and bones
• nerve conduction studies to rule out damage to nerves

A physical examination may also be carried out by a GP or another specialist to check for physical signs of CRPS, such as swelling and changes to your skin's temperature and appearance.

Any physical exam should be gentle so it does not increase your pain.

CRPS can usually be diagnosed if you have clear symptoms of the condition and no other possible cause can be found.

If you're diagnosed with CRPS or the diagnosis is uncertain, you'll usually be referred to a local specialist pain clinic. These are mostly located within hospitals.

Referrals should ideally be made as soon as possible so treatment can be started quickly.