Guillain-Barré syndrome can be difficult to diagnose because several other conditions can cause similar symptoms.

A GP will refer you to a hospital specialist if they think you might have it or they are not sure what's causing your symptoms.

A GP or specialist may:

• ask about your symptoms, such as how long they've lasted and whether they're getting worse – muscle weakness that's getting worse over time is a common sign of Guillain-Barré syndrome
• examine your hands, feet or limbs to check for symptoms such as numbness
• ask if you've recently been ill – Guillain-Barré syndrome often follows an infection such as food poisoning or flu
• check your reflexes, such as whether your leg twitches when your knee is tapped in a particular place – people with Guillain-Barré syndrome usually have no or reduced reflexes

In hospital, 2 tests may be carried out to see how well your nerves are working.

These are:

• electromyography (EMG) – tiny needles are inserted into your muscles and electrical recordings are taken to see how they react when nearby nerves are activated
• nerve conduction studies – small discs (electrodes) are stuck on your skin and minor electric shocks are used to activate the nerves and measure how quickly these signals travel along them

In people with Guillain-Barré syndrome, these tests will usually show that signals are not travelling along the nerves properly.

A lumbar puncture is a procedure to remove some fluid from around the spinal cord (the nerves running up the spine) using a needle inserted into the lower part of the spine.

The sample of fluid will be checked for signs of problems that can cause similar symptoms to Guillain-Barré syndrome, such as an infection.