A narcolepsy diagnosis requires several tests. A doctor will perform a physical exam and an in-depth medical history to rule out other causes of symptoms. Keep in mind that having some of the major symptoms of narcolepsy doesn't necessarily mean you have narcolepsy.
In addition, several specialized tests, which can be performed in a sleep disorders clinic, usually are required before a diagnosis can be established. Two tests that are considered essential in confirming a diagnosis of narcolepsy are the polysomnogram (PSG) and the multiple sleep latency test (MSLT). In addition, questionnaires, such as the Epworth Sleepiness Scale, are often used to measure excessive daytime sleepiness.