A number of tests may be used to diagnose peripheral neuropathy and its underlying cause.
When you see your GP, they'll ask about your symptoms and examine the affected area of your body. This may involve testing sensation, strength and reflexes.
Your doctor may also arrange blood tests, especially to check for causes such as diabetes or vitamin B12 deficiency.
Confirming if you have a neuropathy
Some people may need to see a neurologist (a specialist in conditions affecting the nervous system) in hospital for further tests such as:
- a nerve conduction test (NCS) – where small metal wires called electrodes are placed on your skin which release tiny electric shocks that stimulate your nerves; the speed and strength of the nerve signal is measured
- electromyography (EMG) – where a small needle is inserted through your skin into your muscle and used to measure the electrical activity of your muscles
NCS and EMG are usually carried out at the same time.
Identifying the cause of a neuropathy
Your GP can usually identify the underlying cause of a peripheral neuropathy.
If diabetes is suspected, they can usually make a confident diagnosis based on your symptoms, a physical examination and checking the levels of glucose in your blood and urine.
If you're taking a medication known to cause peripheral neuropathy, your GP may temporarily stop or reduce your dose to see whether your symptoms improve.
If the cause is uncertain, you may be referred to a neurologist for more extensive blood tests to check:
- whether you have a rare acquired cause that may be responsible
- whether you have a genetic abnormality, such as Charcot-Marie-Tooth disease
You may need a lumbar puncture to test the cerebrospinal fluid (a clear, colourless fluid that surrounds and supports the brain and spinal cord) for inflammation.
Occasionally, a nerve biopsy may be carried out as part of your diagnosis. This is a minor surgical procedure where a small sample of a peripheral nerve is removed from near your ankle so it can be examined under a microscope.
It's then checked for changes that could be a sign of certain types of peripheral neuropathy. However, nerve biopsies are rarely needed.
You may also need a scan to look for any underlying cause of your neuropathy, such as: