There is no specific lab test that is used to confirm Bell's palsy. Instead, your doctor will diagnose this condition by ruling out other causes of facial paralysis, including stroke or other neurological conditions. He or she will examine your face and study your inability to move upper and/or lower muscles on the affected side of the face.
To help identify other health problems that may be causing the symptoms of Bell's palsy, such as infections or diabetes, sometimes blood tests will be ordered. In diagnosing Bell's palsy, magnetic resonance imaging (MRI) or computed tomography (CT) scans of the face can help your doctor find out if there are other sources of pressure on the facial nerve. Another test called electromyography (EMG) can show if there has been damage to the facial nerves and, if so, how severe the damage is.
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