Trigeminal Neuralgia: Diagnosis
There is no test to detect Trigeminal Neuralgia. TN is diagnosed almost entirely by the patient's described symptoms and by ruling out other sources of facial pain.  In fact, patient history is the most important factor in the diagnosis of TN. The results of a standard neurological physical exam are typically normal in patients with TN.

If your doctor suspects you have TN, he or she may request a magnetic resonance imaging (MRI) scan to rule out multiple sclerosis or a tumor as a cause of the pain.