Guillain-Barré syndrome can be difficult to diagnose in its earliest stages because other disorders may have similar symptoms, and because the exact symptoms experienced may vary from patient to patient.
Your doctor will ask you about your medical history and your symptoms.
Two tests may be performed to help your doctor determine the diagnosis:
Spinal tap — In this test, a needle in inserted into the lower back to draw out some of the cerebrospinal fluid, the liquid that surrounds the spinal cord and brain. The cerebrospinal fluid of people with Guillain-Barré syndrome usually has higher-than-normal levels of protein.
Nerve conduction velocity test — In this test, small metal plates called electrodes are placed on the skin over the nerve to be tested. An electrical impulse is fed through one electrode placed on the upper part of the nerve and picked up by the other electrodes placed on lower parts of the nerve. The test measures how quickly the electrical impulse travels down the nerve from the upper electrode to the lower electrodes. Nerves affected by the disorder will conduct signals more slowly than unaffected nerves.